The Georgia Aquarium, located in Atlanta, Georgia at Pemberton Place, is billed as the "world's largest aquarium" with more than 8.1 million US gallons (31,000 m³) of marine and fresh water housing more than 100,000 animals of 500 different species. The aquarium's notable specimens include four young whale sharks, three beluga whales and two manta rays.
Funded mostly by a $250 million donation from Home Depot co-founder Bernie Marcus, the aquarium was built on a 20 acre (81,000 m²) site north of Centennial Olympic Park in downtown Atlanta. Marcus credited his 60th birthday dinner at the Monterey Bay Aquarium in 1990 as among the inspirations behind his desire to build an aquarium in Atlanta.

History and admissions
In November 2001, Bernard Marcus announced his idea to build an aquarium as a present to Atlanta, Georgia that would encourage both education and economic growth. Marcus and his wife Billi visited 56 aquariums in 13 countries to research and design a structure, and finally donated $250 million toward Georgia Aquarium’s construction.An additional $40 million dollars in financial contributions was donated by major corporations including the Coca-Cola Company, Turner Broadcasting, Home Depot, UPS, AirTran Airways, BellSouth, Georgia Pacific, Time Warner, SunTrust and Southern Company.The corporate donations allowed the aquarium to open debt free.
Marcus hired Jeff Swanagan, the then CEO of the Florida Aquarium, as the Georgia Aquarium's first employee in 2002.Swanagan had been credited with turning around the financially troubled Florida Aquarium during his tenure as CEO.Swanagan would become the Georgia Aquarium's founding president and executive director, and is largely credited with the creation of the aquarium.He oversaw every aspect in the creation of the aquarium,from the design of the structure to the procurement of animals for the exhibits.
After 27 months and with 60 animal habitats, 16,400 square feet (1,520 m2) of ball room space, 2 food service kitchens, gift shops, a 4-D theater, an on-site restaurant, and a parking lot, the Georgia Aquarium opened first on November 21, 2005 to annual pass holders and then on November 23, 2005 to the general public. At $26 per adult, $21.50 for Seniors, and $19.50 for Children, the price of admission to the non-profit aquarium is among the most expensive in the country. The aquarium has nevertheless far exceeded visitor expectations, welcoming its 1 millionth guest on March 1, 2006, only ninety-eight days after opening. The aquarium sold over 290,000 annual passes for its first year, before sales were halted (to avoid a "private club" atmosphere, according to Aquarium Executive Director Jeff Swanagan).The Georgia Aquarium welcomed its three millionth guest on August 24, 2006, its five millionth on May 23, 2007, and its ten millionth guest on June 25, 2009.

Jeff Swanagan remained the president and chief executive of the Georgia Aquarium until 2008, when he departed to join the Columbus Zoo.He was succceeded as president by Anthony Godfrey.Godfrey had originally been hired by Swanagan in 2004 as the aquarium's chief financial officer.

Collection
Whale shark in the viewing theatreThe Georgia Aquarium contains between 100,000 and 120,000 fish and other sea creatures, representing more than five hundred species. On June 14, 2005, the total number of specimens was unveiled after having previously being reported as "over 55,000". Marcus was quoted in the Atlanta Journal-Constitution as saying: "I have been saying that we would have more than 55,000 fish; I just never said how many more." The fish were transported from Taiwan to the aquarium by UPS in 42 tanks aboard an MD-11. UPS donated the cost of the shipping, estimated at over $200,000 US currency.
The aquarium's most famous specimens were four young whale sharks from Taiwan named Ralph, Norton, Alice and Trixie, after the primary characters from The Honeymooners. Ralph died from peritonitis on January 11, 2007, and Norton followed on June 13, 2007 when the aquarium made the decision to euthanize him after he had shown signs of erratic swimming and had stopped eating.Ralph and Norton were with the Georgia Aquarium at its opening; Alice and Trixie joined the aquarium June 3, 2006.
The Georgia Aquarium is the only institution outside of Asia to house whale sharks. The sharks are kept in a 6.3 million gallon (24,000 m³) tank, and the aquarium was actually designed around the whale shark exhibit.The importation of the whale sharks from Taiwan, which was overseen by Jeff Swanagan and staff biologists, was "top secret" and had never been attempted previously.The move required the use of large aircraft, trucks and boats to ship the massive aquatic animals to Atlanta.The four whale sharks were taken from Taiwan's annual fishing kill quota, which the country has since abolished.Under the quota, the whale sharks would have been killed and eaten if they had not been purchased by the Georgia Aquarium.On May 25, 2007, Taiwan's Fisheries Agency announced the Aquarium had been approved to receive two more whale sharks before Taiwan bans the animals' capture in 2008.On June 1, 2007 the two new whale sharks arrived at the aquarium. The two sharks, caught earlier in 2007, are named Taroko, commemorating Taroko Gorge National Park, and Yushan after Taiwan's Jade Mountain.

The aquarium is currently one of only two aquariums in the United States to exhibit a Great Hammerhead Shark, the other is the Adventure Aquarium.The aquarium was also home to five 11 foot (3 m) long beluga whales. Two males named Nico and Gasper were rescued from a Mexico City amusement park where they lived under a roller coaster. Because of insufficient weight, skin lesions, and a bone disease, on January 2, 2007, Gasper was euthanized.[11] Marina died on December 1, 2007 of what may have been natural causes (she was 25 years old). The remaining females (Natasha and Maris) are on breeding loan from the New York Aquarium. The aquarium is among six other US aquariums, including Chicago's Shedd Aquarium, with belugas in their collections.

Nandi the manta rayContinuing its drive to display marine animals rarely seen in the United States, the aquarium acquired a manta ray from an aquarium facility in Durban, South Africa. Named "Nandi," the manta was caught by accident in nets meant to protect the coast from sharks. Officials at the Durban facility determined that the manta had outgrown its home, and offered the manta to the much-larger Georgia Aquarium. Nandi first went on display in the Ocean Voyager exhibit on August 25, 2008 as the first manta ray on display in the country,and making the aquarium one of only four in the world to display one.A second manta ray was added to the collection in September 2009.

Exhibits
The Ocean Voyager exhibit tunnel
Five Beluga WhalesThe aquatic animals are displayed in five different galleries: Georgia Explorer, Tropical Diver, Ocean Voyager, Cold- Water Quest, and River Scout. Each corresponds to a specific environment. At the left as one enters the aquarium is the Georgia Explorer exhibit, geared especially towards children. It features a number of touch tanks with rays and sharks as well as exhibits featuring sea turtles and the wildlife of Gray's Reef – a National Marine Sanctuary off the Georgia Coast. The second exhibit, River Scout, also reflects regional environments. It features an overhead river where visitors can see North American fish from the bottom up. In addition to local specimens, this exhibit displays piranha, electric fish, and other unusual freshwater life. The third section of the aquarium, Cold Water Quest, features animals from the polar regions of the world and contains most of the mammals in the aquarium's collection. This exhibit includes beluga whales in the aquarium's second largest habitat, California sea lions, Japanese spider crabs, and African black-footed penguins. The fourth exhibit, entitled Ocean Voyager, includes the vast majority of the aquarium's water and almost 100,000 fish. This exhibit is designed to feature the life of the Mesoamerican Barrier Reef System, and showcases the aquarium's whale sharks, as well as a 100 foot (30 m) underwater tunnel and the world's second largest viewing window. The final exhibit takes an artistic turn, as the Tropical Diver exhibit features many curious and haunting forms of aquatic life, including a living reef with live coral. The aquarium also features a "4D" movie "Deepo's Undersea 3D Wondershow", and other attractions, including the Ocean Voyager – Journey With Giants exhibit hall where the Chedd-Angier-Lewis production company, with Electrosonic Inc., has produced the Open Ocean Touchwall, a dynamic, interactive projection for species identification. This is a virtual aquarium where larger than life, fully articulated 3-D renderings of Open Ocean fish swim across six panels assembled to simulate a tank. Guests are invited to reach out and place hands or fingers on the fish. As they do so, fun and informative content bubbles appear to educate the guest about the particular species they have chosen. Also, in 2009, the "Titanic Aquatic" exhibit opened, which features a walkthrough of what it was like on the ship RMS Titanic. The exhibit will only be at the aquarium until September 7, 2009.

The aquarium development was managed by Heery International who served as the Program Manager / Owner's representative for the Georgia Aquarium. The base building was designed by Atlanta-based architecture firm tvsdesign, formerly Thompson, Ventulett, Stainback & Associates. In addition, tvsdesign also did the interior design of the facility as well as the design of the two retail shops located inside the aquarium. The aquarium galleries were designed by the St. Louis based firm of PGAV.

Conservation
Cuttlefish at the aquariumAccording to aquarium founder Bernard Marcus, the aquarium's conservation and environmental mission is just as important as its status as an attraction. Long before opening, the aquarium was already working with Georgia Tech and Georgia State University in Atlanta and the University of Georgia in Athens to help save endangered species through education and research programs.

The acquisition of the male beluga whales, previously suffering in an inadequate environment, was hailed by Marcus as a prime example of the type of conservation activities the Aquarium should be involved with. Approximately 100 tarpon stranded in a tidal pool at Skidaway Island, off the Georgia coast, were rescued for the collection. Coral used in exhibits at the Aquarium is manmade in a collaboration between Georgia Tech and the University of the South Pacific, produced by suspending blocks of pumice over a reef near the village of Tagaqe, Fiji for eight months so that seaweeds and reef invertebrates could establish colonies.

Facilities
The petting tank featuring bonnethead sharks and cownose raysThe Georgia Aquarium, the world’s largest at the time of its opening in November 2005, encompasses 550,000 square feet (5.1 ha; 13 acres) of covered space and includes 328 tons of acrylic windows, 290 plumbing fixtures, 200 floor drains, 53 roof tops, 61 miles (98 km) of wires and pipes and 100,000 yards (91,000 m) of concrete in the structure. It holds 8,000,000 US gallons (30,000 m3) of fresh and salt water (conditioned with 1,500,000 pounds (680 t) of "Instant Ocean" sea salt mix) and houses more than 100,000 fish and animals. The blue metal and glass exterior of the aquarium was designed to resemble a giant ark breaking through a wave. The ship’s hull appears to emerge from two large buildings that feature curved, flowing roofs that were designed to represent ocean swells. The record for largest aquarium in the world is highly contested; however, Dubai's three story Dubai Mall aquarium claims it will be the world's largest when it opens in the new Burj Dubai project.

With an accelerated 27-month schedule, the project timeline for the construction of the aquarium was aggressive. To facilitate the phased construction activities that were essential to meeting the project schedule, two-ply asphalt BUR was installed over a lightweight concrete deck. This temporary roof allowed for expedited construction and the associated roof traffic. The final stage included installation of the light gray FiberTite roofing system, which was selected to match the gray wall panels. Construction of the aquarium was contracted by Brasfield & Gorrie, a general contractor headquartered in Birmingham, Alabama.

In addition to the massive habitats that are the core of the aquarium, the facility includes the 16,400 square feet (1,520 m2) Oceans Ballroom – a banquet hall that can host events for up to 1100 seated or 1600 at a reception. The hall features two 10 by 28 feet (3.0 m × 8.5 m) windows into the exhibits housing the whale sharks and beluga whales. It can also be subdivided into three smaller spaces for events. Chef Wolfgang Puck's company will manage catering services for this facility. The aquarium also includes a fairly large food court with tables extending into the main lobby. The costs of building the aquarium escalated beyond Marcus' original US$250 million donation. To complete the facility without scaling back plans, six local companies — AirTran Airways, BellSouth, Georgia-Pacific, The Home Depot, Southern Company, and SunTrust Banks — signed on as presenting sponsors for exhibits.

In May of 2008, the Georgia Aquarium announced plans to build a $110 million expansion to the facility for a new dolphin exhibit. The expansion will occupy an area of 84,000 square feet (7,800 m2)[4] and will contain 1,300,000 US gallons (4,900 m3) of water. Located on the west side of the facility, the exhibit will feature space for live presentations, observation windows and opportunities for visitors to interact with the animals, which are being lent by Marineland on a breeding loan. This expansion will be self funded by the aquarium, possibly with the help of a corporate sponsor.

Construction began later in 2008, and the scheduled completion date is November 2010, five years after the aquarium first opened. During part of the construction, the aquarium's three beluga whales were temporarily relocated to SeaWorld San Antonio.[14] Beluga whales are very sensitive to sound, and while officials had not noted any excessive amounts of stress, it was decided to remove them anyway and eliminate the possibility.

Location
Aerial view of the aquariumOriginally proposed for the Atlantic Station development in Midtown Atlanta, the Georgia Aquarium is located in downtown Atlanta, just north of Centennial Olympic Park. In addition to the Park and the Aquarium, within a short distance are the Georgia Dome, the Georgia World Congress Center, Philips Arena, and CNN Center. The Coca-Cola Company donated 9 acres (40,000 m²; 4 ha) of land to the site and opened a new World of Coca-Cola attraction on property adjacent to the aquarium. The site is named Pemberton Place in honor of Coca-Cola creator John Pemberton.
Even before opening, the Georgia Aquarium helped drive new development in the area aiding efforts by the City of Atlanta and Central Atlanta Progress, a group of local business leaders, to revitalize downtown. In December 2004, a $300 million office and hotel development was announced for a nearby site. The complex is named Allen Plaza in commemoration of former Atlanta mayor Ivan Allen, Jr., and includes office space for the Southern Company and accounting firm Ernst & Young, as well as W Hotel.

Programs
In June 2008, the aquarium announced its "Swim With Gentle Giants" program. This will allow a dozen divers per day to swim with the whale sharks for $290. There is some controversy over the swim program due to the fact that two of these sharks died in 2007 while in captivity at the Georgia Aquarium. Some experts feel that the human contact would expose the sharks to exotic germs. Visiting divers are instructed to keep a five-foot distance from the whale sharks and other fish while in the in 6.3-million-gallon tank. Divers are also able to document their experience with a $50 commemorative DVD.

The Sahara (Arabic: الصحراء الكبرى‎, aṣ-ṣaḥrā´ al-kubra, "The Greatest Desert") is the world's largest hot desert. At over 9,000,000 square kilometres (3,500,000 sq mi), it covers most of Northern Africa, making it almost as large as the United States or the continent of Europe. The desert stretches from the Red Sea, including parts of the Mediterranean coasts, to the outskirts of the Atlantic Ocean. To the south, it is delimited by the Sahel: a belt of semi-arid tropical savanna that comprises the northern region of central and western Sub-Saharan Africa.

The Sahara has an intermittent history that may go back as much as 3 million years. Some of the sand dunes can reach 180 metres (600 ft) in height.The name comes from the Arabic word for desert: (صَحراء), "ṣaḥrā´" ( صحراء (help·info); /sˤɑħrɑːʔ/).
The Sahara's boundaries are the Atlantic Ocean on the west, the Atlas Mountains and the Mediterranean Sea on the north, the Red Sea and Egypt on the east, and the Sudan and the valley of the Niger River on the south. The Sahara is divided into western Sahara, the central Ahaggar Mountains, the Tibesti Mountains, the Aïr Mountains (a region of desert mountains and high plateaus), Ténéré desert and the Libyan desert (the most arid region). The highest peak in the Sahara is Emi Koussi (3,415 m/11,200 ft) in the Tibesti Mountains in northern Chad.

The Sahara divides the continent of Africa into North and Sub-Saharan Africa. The southern border of the Sahara is marked by a band of semiarid savanna called the Sahel; south of the Sahel lies the lusher Sudan and the Congo River Basin. Most of the Sahara consists of rocky hamada; ergs (large sand dunes) form only a minor part.


People lived on the edge of the desert thousands of years ago since the last ice age. The Sahara was then a much wetter place than it is today. Over 30,000 petroglyphs of river animals such as crocodiles survive, with half found in the Tassili n'Ajjer in southeast Algeria. Fossils of dinosaurs, including Afrovenator, Jobaria and Ouranosaurus, have also been found here. The modern Sahara, though, is not lush in vegetation, except in the Nile Valley, at a few oases, and in the northern highlands, where Mediterranean plants such as the olive tree are found to grow. The region has been this way since about 5000 years ago. Some 2.5 million people currently live in the Sahara, most of these in Egypt, Mauritania, Morocco and Algeria. Dominant ethnicities in the Sahara are various Berber groups including Tuareg tribes, various Arabised Berber groups such as the Hassaniya-speaking Maure (Moors, also known as Sahrawis), and various black African ethnicities including Tubu, Nubians, Zaghawa, Kanuri, Peul (Fulani), Hausa and Songhai. Important cities located in the Sahara include Nouakchott, the capital of Mauritania; Tamanrasset, Ouargla, Bechar, Hassi Messaoud, Ghardaia, El Oued, Algeria; Timbuktu, Mali; Agadez, Niger; Ghat, Libya; and Faya-Largeau, Chad.

Geography
A geographical map of Africa, showing the ecological break that defines the Saharan areaThe Sahara covers huge parts of Algeria, Chad, Egypt, Libya, Mali, Mauritania, Morocco, Niger, Western Sahara, Sudan and Tunisia. It is one of three distinct physiographic provinces of the African massive physiographic division.
The desert landforms of the Sahara are shaped by wind (eolian) or by occasional rains, and include sand dunes and dune fields or sand seas (erg), stone plateaus (hamada), gravel plains (reg), dry valleys (wadi), and salt flats (shatt or chott). Unusual landforms include the Richat Structure in Mauritania.

Several deeply dissected mountains and mountain ranges, many volcanic, rise from the desert, including the Aïr Mountains, Ahaggar Mountains, Saharan Atlas, Tibesti Mountains, Adrar des Iforas, and the Red Sea hills. The highest peak in the Sahara is Emi Koussi, a shield volcano in the Tibesti range of northern Chad.
Most of the rivers and streams in the Sahara are seasonal or intermittent, the chief exception being the Nile River, which crosses the desert from its origins in central Africa to empty into the Mediterranean. Underground aquifers sometimes reach the surface, forming oases, including the Bahariya, Ghardaïa, Timimoun, Kufrah, and Siwah.
The central part of the Sahara is hyper-arid, with little vegetation. The northern and southern reaches of the desert, along with the highlands, have areas of sparse grassland and desert shrub, with trees and taller shrubs in wadis where moisture collects.

To the north, the Sahara reaches to the Mediterranean Sea in Egypt and portions of Libya, but in Cyrenaica and the Magreb, the Sahara borders Mediterranean forest, woodland, and scrub ecoregions of northern Africa, which have a Mediterranean climate characterized by a winter rainy season. According to the botanical criteria of Frank White and geographer Robert Capot-Rey,the northern limit of the Sahara corresponds to the northern limit of Date Palm cultivation (Phoenix dactylifera), and the southern limit of Esparto (Stipa tenacissima), a grass typical of the Mediterranean climate portion of the Maghreb and Iberia. The northern limit also corresponds to the 100 mm (3.9 in) isohyet of annual precipitation.

To the south, the Sahara is bounded by the Sahel, a belt of dry tropical savanna with a summer rainy season that extends across Africa from east to west. The southern limit of the Sahara is indicated botanically by the southern limit of Cornulaca monacantha (a drought-tolerant member of the Chenopodiaceae), or northern limit of Cenchrus biflorus, a grass typical of the Sahel.According to climatic criteria, the southern limit of the Sahara corresponds to the 150 mm (5.9 in) isohyet of annual precipitation (note that this is a long-term average, since precipitation varies strongly from one year to another)

The Smithsonian Institution (pronounced /smɪθˈsoʊnɪən/) is an educational and research institute and associated museum complex, administered and funded by the government of the United States and by funds from its endowment, contributions, and profits from its shops and its magazines. Most of its facilities are located in Washington, D.C., but its 19 museums, zoo, and nine research centers include sites in New York City, Virginia, Panama, and elsewhere.It has over 136 million items in its collections,publishes two magazines named Smithsonian (monthly) and Air & Space (bimonthly), and employs the Smithsonian Police to protect visitors, staff, and the property of the museums. The Institution's current logo is a stylized sun.
The Smithsonian Institution is established as a trust instrumentality by act of Congress, and it is functionally and legally a body of the federal government. More than two-thirds of the Smithsonian's workforce of some 6,300 persons are employees of the federal government. The Smithsonian is represented by attorneys from the United States Department of Justice in litigation, and money judgments against the Smithsonian are also paid out of the federal treasury.

The legislation that created the Smithsonian Institution (approved by Congress Aug. 10, 1846) called for the creation of a Board of Regents to govern and administer the organization. This 17-member board meets at least four times a year and includes as ex officio members the Chief Justice of the United States and the Vice President of the United States. The nominal head of the Institution is the Chancellor, an office which has traditionally been held by the Chief Justice. In September 2007, the Board created the position of Chair of the Board of the Board of Regents, a position currently occupied by Patricia Q. Stonesifer of Washington State.

Other members of the Board of Regents are three members of the U.S. House of Representatives appointed by the Speaker of the House; three members of the Senate, appointed by the President pro tempore of the Senate; and nine citizen members, nominated by the Board and approved by the Congress in a joint resolution signed by the President of the United States.Regents who are representatives and senators serve for the duration of their elected term. Citizen Regents serve a maximum of two six-year terms. Regents are compensated on a part-time basis. The chief executive officer of the Smithsonian is the Secretary, who is appointed by the Board of Regents. There have been 12 Secretaries since the Smithsonian was established. The Secretary also serves as secretary to the Board of Regents but is not a voting member of that body. The Secretary of the Smithsonian has the privilege of the floor at the United States Senate.

Windsor Castle, in Windsor in the English country of Berkshire, is the largest inhabited castle in the world and, dating back to the time of William the Conqueror, is the oldest in continuous occupation.[1] The castle's floor area is approximately 484,000 square feet (44,965 square metres).[2]

Together with Buckingham Palace in London and Holyrood Palace in Edinburgh, it is one of the principal official residences of the British monarch. Queen Elizabeth II spends many weekends of the year at the castle, using it for both state and private entertaining. Her other two residences, Sandringham House and Balmoral Castle, are the Royal Family's private homes.

Most of the Kings and Queens of England, later Kings and Queens of Great Britain, and later still kings and queens of the United Kingdom and the other Commonwealth realms, have had a direct influence on the construction and evolution of the castle, which has been their garrison fortress, home, official palace, and sometimes their prison. Chronologically the history of the castle can be traced through the reigns of the monarchs who have occupied it. When the country has been at peace, the castle has been expanded by the additions of large and grand apartments; when the country has been at war, the castle has been more heavily fortified. This pattern has continued to the present day.

London Heathrow Airport or Heathrow (IATA: LHR, ICAO: EGLL), located in the London Borough of Hillingdon, is the world's busiest airport in terms of international passenger traffic. It is the world's second busiest airport in total passenger traffic. It is also the largest and busiest airport in the United Kingdom. It is also the busiest in the European Union in terms of passenger traffic and the second busiest in terms of traffic movements.[3] Heathrow is owned and operated by BAA, which also owns and operates six other UK airports.[4] BAA in turn is owned by an international consortium led by Spain's Ferrovial Group.[5] Heathrow is the primary hub of British Airways, BMI and Virgin Atlantic.

Located 12 NM (22 km; 14 mi) west[1] of Central London, Heathrow originally was designed to have six runways in three pairs spaced approximately 120 degrees apart but now has just two parallel main runways running east-west and five terminals. The site covers 12.14 square kilometres (4.69 sq mi). Terminal 5 was officially opened by H.M. Queen Elizabeth II on 14 March 2008 and opened to passengers on 27 March 2008. Construction of Heathrow East, to replace Terminal 2 and The Queen's Building, began in 2009, and is expected to be completed in 2013.[6] Terminals 3 and 4 will also be refurbished during this period.[7] In November 2007 a consultation process began for the building of a new third runway and was controversially[8] approved on 15 January 2009 by UK Government ministers.[9]

Heathrow Airport has a CAA Public Use Aerodrome Licence (Number P527) that allows flights for the public transport of passengers or for flying instruction.[10]

San Alfonso del Mar is a resort located in Algarrobo, Chile frequently noted because of its 1,000-meter long, 19-acre outdoor pool, which holds a Guinness world record[1] as the largest in the world. The resort's large pool utilizes a technology developed by the Chilean company Crystal Lagoons, which uses water pumped from the Pacific Ocean, that is then filtered and treated for supply to the pool.

It has been reported to have a depth of 35 meters (115 feet)[2][3] which would make it the world's deepest pool, however this appears to stem from confusion over it being "transparent to a depth of 35 meters".

0
The Amazon River (Portuguese: Rio Amazonas; Spanish: Río Amazonas; pronounced /ˈæməzɒn/ (US); pronounced /ˈæməzən/ (UK)) of South America is the largest river in the world by volume, with a total river flow greater than the next eight largest rivers combined. The Amazon, which has the largest drainage basin in the world, accounts for approximately one-fifth of the world's total river flow. During the wet season parts of the Amazon exceed 190 kilometres (120 mi) in width. Because of its vast dimensions, it is sometimes called The River Sea. At no point is the Amazon crossed by bridges.This is not because of its huge dimensions; in fact, for most of its length, the Amazon's width is well within the capability of modern engineers to bridge. However, the bulk of the river flows through tropical rainforest, where there are few roads and even fewer cities, so there is no need for crossings.
While the Amazon is the largest river in the world by most measures, the current consensus within the geographic community holds that the Amazon is the second longest river, just slightly shorter than the Nile. However, some scientists, particularly from Brazil and Peru, dispute this
Drainage area
The Amazon basin, the largest drainage basin in the world, covers about 40 percent of South America, an area of approximately 6,915,000 square kilometres (2,670,000 sq mi) . It gathers its waters from 5 degrees north latitude to 20 degrees south latitude. Its most remote sources are found on the inter-Andean plateau, just a short distance from the Pacific Ocean.
The area covered by the water of the Amazon River and its tributaries more than triples over the course of a year. In an average dry season 110,000 square kilometres (42,000 sq mi)of land are water-covered, while in the wet season the flooded area of the Amazon Basin rises to 350,000 square kilometres (135,000 sq mi).

The quantity of water released by the Amazon to the Atlantic Ocean is enormous: up to 300,000 m³ per second in the rainy season. The Amazon is responsible for about 20%of the total volume of fresh water entering the oceans worldwide.Offshore of the mouth of the Amazon, potable water can be drawn from the ocean while still out of sight of the coastline, and the salinity of the ocean is notably lower five hundred kilometres out to sea.
Origins
The Amazon originates from the Apacheta cliff in Arequipa at the Nevado Mismi, with a sole sign of a wooden cross.
Source of the Amazon
Meeting of Waters is the confluence of the Rio Negro (black) and the Rio Solimões (sandy) near Manaus, Brazil.The Upper Amazon has a series of major river systems in Peru and Ecuador, some of which flow into the Marañón and others directly into the Amazon proper. Among others, these include the following rivers: Morona, Pastaza, Nucuray, Urituyacu, Chambira, Tigre, Nanay, Napo, Huallaga, and Ucayali. The headstreams of the Marañón—which for many years had been seen as the origin of the Amazon—flow from high above central Peru's Lake Lauricocha, from the glaciers in what is known as the Nevado de Yarupa. Rushing through waterfalls and gorges in an area of the high jungle called the pongos, the Marañón River flows about 1,600 kilometres (990 mi) from west-central to northeast Peru before it combines with the Ucayali River, just below the provincial town of Nauta, to form the Amazon River.

The most distant source of the Amazon was firmly established in 1996, 2001 and 2007] as a glacial stream on a snowcapped 5,597 m (18,360 ft) peak called Nevado Mismi in the Peruvian Andes, roughly 160 km (99 mi) west of Lake Titicaca and 700 km (430 mi) southeast of Lima. The waters from Nevado Mismi flow into the Quebradas Carhuasanta and Apacheta, which flow into the Río Apurímac which is a tributary of the Ucayali which later joins the Marañón to form the Amazon proper. (While this is the point at which most geographers place the beginning of the Amazon proper, in Brazil the river is known at this point as the Solimões das Águas). Soon thereafter the darkly colored waters of the Rio Negro meet the sandy colored Rio Solimões, and for over 6 km (4 mi) these waters run side by side without mixing.

After the confluence of Río Apurímac and Ucayali, the river leaves Andean terrain and is instead surrounded by flood plain. From this point to the Marañón, some 1,600 km (990 mi) , the forested banks are just out of water, and are inundated long before the river attains its maximum flood-line. The low river banks are interrupted by only a few hills, and the river enters the enormous Amazon Rainforest.

The river systems and flood plains in Brazil, Peru, Ecuador, Colombia and Venezuela whose waters drain into the Solimões and its tributaries are called the "Upper Amazon". The Amazon River proper runs mostly through Brazil and Peru, and it has tributaries reaching into Venezuela, Colombia, Ecuador, and Bolivia.

Flooding
A NASA satellite image of a flooded portion of the river.Not all of the Amazon's tributaries flood at the same time of the year. Many branches begin flooding in November, and may continue to rise until June. The rise of the Rio Negro starts in February or March, and it also begins to recede in June. The Madeira rises and falls two months earlier than most of the rest of the Amazon.

The average depth of the river in the height of the rainy season is 40 metres (130 ft) and the average width can be nearly 40 km (25 mi)[citation needed].

The main river (which is between approximately one and six miles (10 km) wide) is navigable for large ocean steamers to Manaus, 1,500 kilometres (930 mi) upriver from the mouth. Smaller ocean vessels of 3,000 tons or 9,000 tons[6] and 5.5 metres (18 ft) draft can reach as far as Iquitos, Peru, 3,600 kilometres (2,200 mi) from the sea. Smaller riverboats can reach 780 kilometres (480 mi) higher as far as Achual Point. Beyond that, small boats frequently ascend to the Pongo de Manseriche, just above Achual Point.


Geography
This article may require cleanup to meet Wikipedia's quality standards. Please improve this article if you can. (August 2009)
A satellite image of the mouth of the Amazon River, looking southAt some points, for long distances, the river divides into two main streams with inland and lateral channels, all connected by a complicated system of natural canals, cutting the low, flat igapo lands, which are never more than 5 metres (16 ft) above low river, into many islands.
From the town of Canaria at the great bend of the Amazon to the Negro, only very low land is found, resembling that at the mouth of the river.Vast areas of land in this region are submerged at high water, above which only the upper part of the trees of the sombre forests appear. Near the mouth of the Rio Negro to Serpa, nearly opposite the river Madeira, the banks of the Amazon are low, until approaching Manaus, they rise to become rolling hills. At Óbidos, a bluff 17 m (56 ft) above the river is backed by low hills. The lower Amazon seems to have once been a gulf of the Atlantic Ocean, the waters of which washed the cliffs near Óbidos.

Only about 10% of the water discharged by the Amazon enters the mighty stream downstream of Óbidos, very little of which is from the northern slope of the valley. The drainage area of the Amazon basin above Óbidos city is about 5 million square kilometres (2,000,000 sq mi), and, below, only about 1 million square kilometres (400,000 sq mi or around 20%), exclusive of the 1.4 million square kilometres (540,000 sq mi) of the Tocantins basin.

In the lower reaches of the river, the north bank consists of a series of steep, table-topped hills extending for about 240 kilometres (150 mi) from opposite the mouth of the Xingu as far as Monte Alegre. These hills are cut down to a kind of terrace which lies between them and the river.

On the south bank, above the Xingu, an almost-unbroken line of low bluffs bordering the flood-plain extends nearly to Santarém, in a series of gentle curves before they bend to the south-west, and, abutting upon the lower Tapajós, merge into the bluffs which form the terrace margin of the Tapajós river valley.

Mouth
Mouth of the Amazon RiverThe definition of what exactly and how wide is the mouth of the Amazon is a matter of dispute, because of the area's peculiar geography. Most particularly, sometimes the Pará River is included, whereas sometimes it is just considered the independent lower reach of the Tocantins River. The Pará river estuary alone is 60 km (37 mi) wide. The Pará and the Amazon are connected by a series of river channels called furos near the town of Breves; between them lies Marajó, an island almost the size of Switzerland that is the world's largest combined river/sea island.
If the Pará river and the Marajó island ocean frontage are included, the Amazon estuary is some 330 kilometres (210 mi) wide. In this case, the width of the mouth of the river is usually measured from Cabo Norte, in the Brazilian state of Amapá, to Ponta da Tijoca near the town of Curuçá, in the state of Pará. By this criterion, the Amazon is wider at its mouth than the entire length of the Thames in England.

A more conservative measurement excluding the Pará river estuary, from the mouth of the Araguari River to Ponta do Navio on the northern coast of Marajó, would still give the mouth of the Amazon a width of over 180 kilometres (110 mi). If only the river's main channel is considered, between the islands of Curuá (state of Amapá) and Jurupari (state of Pará), the width falls to just about 15 kilometres (9.3 mi) - but that is still impressive for any river.

Tidal bore
The tension between the river's strong push and the Atlantic tides causes a phenomenon called a tidal bore, a powerful tidal wave that flows rapidly inland from the sea up the Amazon mouth and nearby coastal rivers several times a year at high tide. Tidal bores also occur in other river mouths around the world, but the Amazon's are among the world's highest and fastest, probably second only to those of Qiantang River in China. In the Amazon, the phenomenon is locally known as the pororoca.

The pororoca occurs especially where depths do not exceed 7 metres (23 ft). It starts with a very loud roar, constantly increasing, and advances at the rate of 15–25 km/h (9–16 mph), with a breaking wall of water 1.5–4.0-metres (5–13 ft) high that may travel violently several kilometres up the Amazon and other rivers close to its mouth. It is particularly intense in the rivers of the coast of the state of Amapá north of the mouth of the Amazon, such as the Araguari River, but can be observed in Pará rivers as well.
The bore is the reason the Amazon does not have a protruding delta; the ocean rapidly carries away the vast volume of silt carried by the Amazon, making it impossible for a delta to grow past the shoreline.[clarification needed] The region also has very high tides, sometimes reaching 6 metres (20 ft) and has become a popular spot for river surfing.[7]
Wildlife
More than one-third of all species in the world live in the Amazon Rainforest,[8] a giant tropical forest and river basin with an area that stretches more than 5.4 million square kilometres (2,100,000 sq mi) and is among the richest tropical forests in the world. The Amazon River has over 3,000 recognized species of fish and that number is still growing. Some estimates go as high as 5,000.

Characins such as piranha species are prey for the Giant Otter, but these aggressive fish may also pose a danger.Along with the Orinoco, the river is one of the main habitats of the boto, also known as the Amazon river dolphin (Inia geoffrensis). The largest species of river dolphin, it can grow to lengths of up to 2.6 metres (8.5 ft). The boto is the subject of a very famous legend in Brazil, about a dolphin that turns into a man and seduces maidens by the riverside. The tucuxi (Sotalia fluviatilis) is a dolphin found both in the rivers of the Amazon Basin and in the coastal waters of South America.
Also present in large numbers are the notorious piranha, carnivorous fish which congregate in large schools, and may attack livestock and even humans. However, only a few species attack humans, and many are solely fish-eaters, and do not school.
The bull shark (Carcharhinus leucas) has been reported 4,000 km (2,500 mi) up the Amazon River at Iquitos in Peru. The arapaima, known in Brazil as pirarucu (Arapaima gigas) is a South American tropical freshwater fish. It is one of the largest freshwater fish in the world, reportedly with a maximum length in excess of 3 m (9.8 ft) and weight up to 200 kg (440 lb).Another Amazonian freshwater fish is the arowana (or aruanã in Brazil) (Osteoglossum bicirrhosum) which is also a predator and very similar to the arapaima, but reaches a length of maximum 120 centimetres. The candirú are a number of genera of parasitic freshwater catfish in the family Trichomycteridae; all are native to the Amazon River. It sometimes attacks humans and has been known to enter the urethras of bathers.The electric eel (Electrophorus electricus) is found in the Amazon River basin.

The anaconda snake is found in shallow waters in the Amazon basin. One of the world's largest species of snake, the anaconda spends most of its time in the water, with just its nostrils above the surface.

The river supports thousands of species of fish, as well as crabs, algae, and turtles.
Colonial encounters with the Amazon
See also: Timeline of Amazon history
During what many archaeologists call the formative period, Amazonian societies were deeply involved in the emergence of South America's highland agrarian systems, and possibly contributed directly to the social and religious fabric constitutive of the Andean civilizational orders.

In 1500, Vicente Yañez Pinzón was the first European to sail into the river. Pinzón called the river flow Río Santa María del Mar Dulce, later shortened to Mar Dulce (literally, sweet sea, because of its freshwater pushing out into the ocean). For 350 years after the first European encounter of the Amazon by Pinzón, the Portuguese portion of the basin remained an untended former food gathering and planned agricultural landscape occupied by the indigenous peoples who survived the arrival of European diseases. There is ample evidence for complex large-scale, pre-Columbian social formations, including chiefdoms, in many areas of Amazonia (particularly the inter-fluvial regions) and even large towns and cities.For instance the pre-Columbian culture on the island of Marajo may have developed social stratification and supported a population of 100,000 people.The Native Americans of the Amazon rain forest may have used Terra preta to make the land suitable for the large scale agriculture needed to support large populations and complex social formations such as chiefdoms.
One of Gonzalo Pizarro's lieutenants, Francisco de Orellana, during his 1541 expedition, east of Quito into the South American interior in search of El Dorado and the Country of the Cinnamon was ordered to explore the Coca River and return when the river ended. When they arrived to the confluence to the Napo River, his men menaced to mutiny if they did not continue. On 26 December 1541, he accepted to be elected chief of the new expedition and to conquest new lands in name of the king. The 49 men began to build a bigger ship for riverine navigation. During their navigation on Napo River they were threatened constantly by the Omaguas. They reached Negro River on 3 June 1542 and finally arrived to the Amazon River, that was so named because they were allegedly attacked by fierce female warriors like the mythological Amazons. The Icamiaba natives dominated the area close to the Amazon River, rich in gold. When Orellana went down the river in search of gold, descending from the Andes (in 1541), the Amazon was called Grande Río ("Large River"), Mar Dulce ("Sweet[water] Sea") or Río de la Canela ("Cinnamon River," because of the great cinnamon trees that Orellana claimed to have found there - in spite of cinnamon being an Asian plant impossible to be found growing in the wild in 16th-century South America). Orellana narrated the belligerent victory of the Icamiaba women against the Spanish invaders to Charles V, Holy Roman Emperor, who, inspired by the Greek Amazons, baptized the river as Amazonas, the name by which it is still known in both Spanish and Portuguese.
In 1637–38 the Portuguese explorer Pedro Teixeira was the first European to ascend the river from Belém (near the mouth of the Amazon) to Quito, part of the Spanish Viceroyalty of Peru, and then to return the same way. Teixeira's expedition was massive - some 2000 people in 37 large canoes. From 1648 to 1652, António Raposo Tavares lead one of the longest known expeditions from São Paulo to the mouth of the Amazon, investigating many of its tributaries, including the Rio Negro, and covering a distance of more than 10,000 km (6,214 mi).

In what is currently Brazil, Ecuador, Bolivia, Colombia, Peru, and Venezuela, a number of colonial and religious settlements were established along the banks of primary rivers and tributaries for the purpose of trade, slaving and evangelization among the indigenous peoples of the vast rain forest. Father Fritz, apostle of the Omaguas, established some forty mission villages. Charles Marie de La Condamine accomplished the first scientific exploration of the Amazon River.

The Cabanagem, one of the bloodiest regional wars ever in Brazil, which was chiefly directed against the white ruling class, reduced the population of Pará from about 100,000 to 60,000.
The total population of the Brazilian portion of the Amazon basin in 1850 was perhaps 300,000, of whom about two-thirds comprised by Europeans and slaves, the slaves amounting to about 25,000. The Brazilian Amazon's principal commercial city, Pará (now Belém), had from 10,000 to 12,000 inhabitants, including slaves. The town of Manáos, now Manaus, at the mouth of the Rio Negro, had a population between 1,000 to 1,500. All the remaining villages, as far up as Tabatinga, on the Brazilian frontier of Peru, were relatively small.

Post-colonial history
On 6 September 1850, the emperor, Pedro II, sanctioned a law authorizing steam navigation on the Amazon, and gave the Viscount of Mauá (Irineu Evangelista de Sousa) the task of putting it into effect. He organized the "Companhia de Navegação e Comércio do Amazonas" in Rio de Janeiro in 1852; and in the following year it commenced operations with three small steamers, the Monarch, the Marajó and Rio Negro.

Henry Walter Bates was most famous for his expedition to the Amazon (1848–1859).At first, navigation was principally confined to the main river; and even in 1857 a modification of the government contract only obliged the company to a monthly service between Pará and Manaus, with steamers of 200 tons cargo capacity, a second line to make six round voyages a year between Manaus and Tabatinga, and a third, two trips a month between Pará and Cametá. This was the first step in opening up the vast interior.

The success of the venture called attention to the opportunities for economic exploitation of the Amazon, and a second company soon opened commerce on the Madeira, Purus and Negro; a third established a line between Pará and Manaus; and a fourth found it profitable to navigate some of the smaller streams. In that same period, the Amazonas Company was increasing its fleet. Meanwhile, private individuals were building and running small steam craft of their own on the main river as well as on many of its tributaries.

On 31 July 1867 the government of Brazil, constantly pressed by the maritime powers and by the countries encircling the upper Amazon basin, especially Peru, decreed the opening of the Amazon to all flags; but limited this to certain defined points: Tabatinga — on the Amazon; Cametá — on the Tocantins; Santarém — on the Tapajós; Borba — on the Madeira, and Manaus — on the Rio Negro. The Brazilian decree took effect on 7 September 1867.

Thanks in part to the mercantile development associated with steam boat navigation, coupled with the internationally driven demand for natural rubber (1880-1920), Manáos (now Manaus) and Pará (now Belém) in (Brazil), and Iquitos, Peru became thriving, cosmopolitan centers of commerce and spectacular — albeit illusory —"modern" "urban growth". This was particularly the case for Iquitos during its late 19th and early 20th century Rubber Bonanza zenith when this dynamic boomtown was known abroad as the St. Louis of the Amazon.

The first direct foreign trade with Manaus was commenced around 1874. Local trade along the river was carried on by the English successors to the Amazonas Company — the Amazon Steam Navigation Company — as well as numerous small steamboats, belonging to companies and firms engaged in the rubber trade, navigating the Negro, Madeira, Purus and many other tributaries, such as the Marañón to ports as distant as Nauta, Peru. The Amazon Steam Navigation Company had 38 vessels.
By the turn of the 20th century, the principal exports of the Amazon Basin were India-rubber, cacao, Brazil nuts and a few other products of minor importance, such as pelts and exotic forest produce (resins, barks, woven hammocks, prized bird feathers, live animals, etc.) and extracted goods (lumber, gold, etc.).
20th century concerns
Four centuries after the European discovery of the Amazon river, the total cultivated area in its basin was probably less than 65 square kilometres (25 sq mi), excluding the limited and crudely cultivated areas among the mountains at its extreme headwaters. This situation changed dramatically during the 20th century.
Manaus, the largest city in the Amazon valley, as seen from a NASA satellite image, surrounded by the dark Rio Negro and the muddy Amazon River.Wary of foreign exploitation of the nation's resources, Brazilian governments in the 1940s set out to develop the interior, away from the seaboard where foreigners owned large tracts of land. The original architect of this expansion was President Getúlio Vargas, the demand for rubber from the Allied forces in World War II providing funding for the drive.

The construction of the new capital city of Brasilia in the interior in 1960 also contributed to the opening up of the Amazon basin. A large-scale colonization program saw families from Northeastern Brazil relocated to the forests, encouraged by promises of cheap land. Many settlements grew along the road from Brasilia to Belém, but rainforest soil proved difficult to cultivate.
Still, long-term development plans continued. Roads were cut through the forests, and in 1970, the work on the Trans-Amazonian highway (Transamazônica) network began. The network's three pioneering highways were completed within ten years, but never fulfilled their promise, large portions of the Trans-Amazonian and accessory roads such as BR-319 (Manaus-Porto Velho) being derelict and impassable in the rainy season.

With a current population of 1.8 million people, Manaus is the Amazon’s largest city. Manaus alone represents approximately 50% of the population of the Brazilian state of Amazonas, which is the largest state. The racial makeup of the city is 64% Pardo (Mulatto and mestizo) and 32% White.
Dispute regarding length

While debate as to whether the Amazon or the Nile is the world's longest river has gone on for many years, the historic consensus of geographic authorities has been to regard the Amazon as the second longest river in the world, with the Nile being the longest. However, the Amazon has been measured by different geographers as being anywhere between 6,259 and 6,800 kilometres (3,889–4,225 mi) long. The Nile is reported to be anywhere from 5,499 to 6,690 kilometres (3,417–4,157 mi). The differences in these measurements often result from the use of different definitions.

A study by Brazilian scientists claimed that the Amazon is actually longer than the Nile. Using Nevado Mismi, which in 2001 was labeled by the National Geographic Society as the Amazon's source, these scientists have made new calculations of the Amazon's length. They now estimate that the Amazon is 105 kilometres (65 mi) longer than the Nile,and Guido Gelli, director of science at the Brazilian Institute of Geography and Statistics (IBGE), told the Brazilian TV network Globo in June 2007 that it could be considered as a fact that the Amazon was the longest river in the world. However, other geographers have had access to the same data since 2001, and a consensus has yet to emerge to support the claims of these Brazilian scientists.

The Akashi-Kaikyō Bridge (明石海峡大橋, Akashi Kaikyō Ō-hashi?), also known as the Pearl Bridge, is the world's longest suspension bridge (measured by the length of the center span of 1,991 metres/6,532 feet/1.24 miles). It is located in Japan and was completed in 1998[1]. The bridge links the city of Kobe on the mainland of Honshū to Iwaya on Awaji Island by crossing the busy Akashi Strait. It carries part of the Honshū-Shikoku Highway.
The bridge is one of the key links of the Honshū-Shikoku Bridge Project, which created three routes across the Inland Sea.

History
Before the Akashi Kaikyō Bridge was built, ferries carried passengers across the Akashi Strait in Japan. This dangerous waterway often experiences severe storms, and in 1955, two ferries sank in the strait during a storm, killing 168 children. The ensuing shock and public outrage convinced the Japanese government to develop plans for a suspension bridge to cross the strait. The original plan called for a mixed railway-road bridge, but when construction on the bridge began in April 1986, the construction was restricted to road only, with six lanes. Actual construction did not begin until May 1986, and the bridge was opened for traffic on April 5, 1998. The Akashi Strait is an international waterway that necessitated the provision of a 1,500-metre (4,921 ft)-wide shipping lane.

Architecture
The bridge has three spans. The central span is 1,991 m (6,532 ft)[1], and the two other sections are each 960 m (3,150 ft). The bridge is 3,911 m (12,831 ft) long overall. The central span was originally only 1,990 m (6,529 ft), but the Kobe earthquake on January 17, 1995, moved the two towers sufficiently (only the towers had been erected at the time) so that it had to be increased by 1 m (3.3 ft).[1]

The bridge was designed with a two-hinged stiffening girder system, allowing the structure to withstand winds of 286 kilometres per hour (178 mph), earthquakes measuring to 8.5 on the Richter scale, and harsh sea currents. The bridge also contains pendulums that are designed to operate at the resonance frequency of the bridge to damp forces. The two main supporting towers rise 298 m (978 ft) above sea level, and the bridge can expand because of heating up to 2 metres (7 ft) over the course of a day. Each anchorage required 350,000 tonnes (340,000 LT; 390,000 ST) of concrete. The steel cables have 300,000 kilometres (190,000 mi) of wire: each cable is 112 centimetres (44 in) in diameter and contains 36,830 strands of wire.

The total cost is estimated at ¥500 billion, and is expected to be defrayed by charging commuters a toll to cross the bridge. The toll is ¥2,300 and is used by approximately 23,000 cars/day.[4]
Nearby attractions
Two parks in proximity of the bridge have been built for tourists, one in Maiko (including a small museum) and one in Asagiri. Both are accessible by the coastal train line.

The Great Wall of China (simplified Chinese: 长城; traditional Chinese: 長城; pinyin: Chángchéng; literally "long city/fortress") or (simplified Chinese: 万里长城; traditional Chinese: 萬里長城; pinyin: Wànlǐ Chángchéng; literally "The long wall of 10,000 Li (里)"[1]) is a series of stone and earthen fortifications in northern China, built, rebuilt, and maintained between the 5th century BC and the 16th century to protect the northern borders of the Chinese Empire from Xiongnu attacks during various successive dynasties. Since the 5th century BC, several walls have been built that were referred to as the Great Wall. One of the most famous is the wall built between 220–206 BC by the first Emperor of China, Qin Shi Huang. Little of that wall remains; the majority of the existing wall were built during the Ming Dynasty.

The Great Wall stretches from Shanhaiguan in the east to Lop Nur in the west, along an arc that roughly delineates the southern edge of Inner Mongolia. The most comprehensive archaeological survey, using advanced technologies, has recently concluded that the entire Great Wall, with all of its branches, stretches for 8,851.8 km (5,500.3 mi). This is made up of 6,259.6 km (3,889.5 mi) of sections of actual wall, 359.7 km (223.5 mi) of trenches and 2,232.5 km (1,387.2 mi) of natural defensive barriers such as hills and rivers.

History
Great Wall of the Ming Dynasty
Map of the whole wall constructionsThe Chinese were already familiar with the techniques of wall-building by the time of the Spring and Autumn Period, which began around the 8th century BC. During the Warring States Period from the 5th century BC to 221 BC, the states of Qi, Yan and Zhao all constructed extensive fortifications to defend their own borders. Built to withstand the attack of small arms such as swords and spears, these walls were made mostly by stamping earth and gravel between board frames. Qin Shi Huang conquered all opposing states and unified China in 221 BC, establishing the Qin Dynasty. Intending to impose centralized rule and prevent the resurgence of feudal lords, he ordered the destruction of the wall sections that divided his empire along the former state borders. To protect the empire against intrusions by the Xiongnu people from the north, he ordered the building of a new wall to connect the remaining fortifications along the empire's new northern frontier. Transporting the large quantity of materials required for construction was difficult, so builders always tried to use local resources. Stones from the mountains were used over mountain ranges, while rammed earth was used for construction in the plains. There are no surviving historical records indicating the exact length and course of the Qin Dynasty walls. Most of the ancient walls have eroded away over the centuries, and very few sections remain today. Later, the Han, Sui, Northern and Jin dynasties all repaired, rebuilt, or expanded sections of the Great Wall at great cost to defend themselves against northern invaders.

The Great Wall concept was revived again during the Ming Dynasty following the Ming army's defeat by the Oirats in the Battle of Tumu in 1449. The Ming had failed to gain a clear upper-hand over the Manchurian and Mongolian tribes after successive battles, and the long-drawn conflict was taking a toll on the empire. The Ming adopted a new strategy to keep the nomadic tribes out by constructing walls along the northern border of China. Acknowledging the Mongol control established in the Ordos Desert, the wall followed the desert's southern edge instead of incorporating the bend of the Huang He.

Photograph of the Great Wall in 1907Unlike the earlier Qin fortifications, the Ming construction was stronger and more elaborate due to the use of bricks and stone instead of rammed earth. As Mongol raids continued periodically over the years, the Ming devoted considerable resources to repair and reinforce the walls. Sections near the Ming capital of Beijing were especially strong.[citation needed]

During the 1440s–1460s, the Ming also built a so-called "Liaodong Wall". Similar in function to the Great Wall (whose extension, in a sense, it was), but more basic in construction, the Liaodong Wall enclosed the agricultural heartland of the Liaodong province, protecting it against potential incursions by Jurched-Mongol Oriyanghan from the northwest and the Jianzhou Jurchens from the north. While stones and tiles were used in some parts of the Liaodong Wall, most of it was in fact simply an earth dike with moats on both sides.

Towards the end of the Ming Dynasty, the Great Wall helped defend the empire against the Manchu invasions that began around 1600. Under the military command of Yuan Chonghuan, the Ming army held off the Manchus at the heavily fortified Shanhaiguan pass, preventing the Manchus from entering the Chinese heartland. The Manchus were finally able to cross the Great Wall in 1644, when the gates at Shanhaiguan were opened by Wu Sangui, a Ming border general who disliked the activities of rulers of the Shun Dynasty. The Manchus quickly seized Beijing, and defeated the newly founded Shun Dynasty and remaining Ming resistance, to establish the Qing Dynasty.

In 2009, an additional 290 kilometres (180 miles) of previously undetected portions of the wall, built during the Ming Dynasty, were discovered. The newly discovered sections range from the Hushan mountains in the northern Liaoning province to Jiayuguan in western Gansu province. The sections had been submerged over time by sandstorms that moved across the arid region.
Under Qing rule, China's borders extended beyond the walls and Mongolia was annexed into the empire, so construction and repairs on the Great Wall were discontinued.

Notable areas
An area of the sections of the Great Wall at Jinshanling
The Great WallSome of the following sections are in Beijing municipality, which were renovated and which are regularly visited by modern tourists today.

"North Pass" of Juyongguan pass, known as the Badaling. When used by the Chinese to protect their land, this section of the wall has had many guards to defend China’s capital Beijing. Made of stone and bricks from the hills, this portion of the Great Wall is 7.8 meters (25.6 ft) high and 5 meters (16.4 ft) wide.
"West Pass" of Jiayuguan (pass). This fort is near the western edges of the Great Wall.

"Pass" of Shanhaiguan. This fort is near the eastern edges of the Great Wall.
One of the most striking sections of the Ming Great Wall is where it climbs extremely steep slopes. It runs 11 kilometers (7 mi) long, ranges from 5 to 8 meters (16–26 ft) in height, and 6 meters (19.7 ft) across the bottom, narrowing up to 5 meters (16.4 ft) across the top. Wangjinglou is one of Jinshanling's 67 watchtowers, 980 meters (3,215 ft) above sea level.
South East of Jinshanling, is the Mutianyu Great Wall which winds along lofty, cragged mountains from the southeast to the northwest for approximately 2.25 kilometers (about 1.3 miles). It is connected with Juyongguan Pass to the west and Gubeikou to the east.
25 km west of the Liao Tian Ling stands of part of Great wall which is only 2~3 stories high. According to the records of Lin Tian, the wall was not only extremely short compared to others, but it appears to be silver. Archeologists explain that the wall appears to be silver because the stone they used were from Shan Xi, where many mines are found. The stone contains extremely high metal in it causing it to appear silver. However, due to years of decay of the Great Wall, it is hard to see the silver part of the wall today.
Another notable section lies near the eastern extremity of the wall, where the first pass of the Great Wall was built on the Shanhaiguan (known as the “Number One Pass Under Heaven”), the first mountain the Great Wall climbs. Jia Shan is also here, as is the Jiumenkou, which is the only portion of the wall that was built as a bridge. Shanhaiguan Great Wall is called the “Museum of the Construction of the Great Wall”, because of the Meng Jiang-Nu Temple, built during the Song Dynasty.

Characteristics
The Great Wall on an 1805 mapBefore the use of bricks, the Great Wall was mainly built from Earth or Taipa, stones, and wood.
During the Ming Dynasty, however, bricks were heavily used in many areas of the wall, as were materials such as tiles, lime, and stone. The size and weight of the bricks made them easier to work with than earth and stone, so construction quickened. Additionally, bricks could bear more weight and endure better than rammed earth. Stone can hold under its own weight better than brick, but is more difficult to use. Consequently, stones cut in rectangular shapes were used for the foundation, inner and outer brims, and gateways of the wall. Battlements line the uppermost portion of the vast majority of the wall, with defensive gaps a little over 30 cm (one foot) tall, and about 23 cm (9 inches) wide.

Condition
The Great Wall in fogWhile some portions north of Beijing and near tourist centers have been preserved and even extensively renovated, in many locations the Wall is in disrepair. Those parts might serve as a village playground or a source of stones to rebuild houses and roads.[7] Sections of the Wall are also prone to graffiti and vandalism. Parts have been destroyed because the Wall is in the way of construction.

More than 60 kilometres (37 mi) of the wall in Gansu province may disappear in the next 20 years, due to erosion from sandstorms. In places, the height of the wall has been reduced from more than five meters (16.4 ft) to less than two meters. The square lookout towers that characterize the most famous images of the wall have disappeared completely. Many western sections of the wall are constructed from mud, rather than brick and stone, and thus are more susceptible to erosion.[9]

Watchtowers and barracks
WatchtowerCommunication between the army units along the length of the Great Wall, including the ability to call reinforcements and warn garrisons of enemy movements, was of high importance. Signal towers were built upon hill tops or other high points along the wall for their visibility.

Visibility from space
The Great Wall of China as seen in a false-color radar image from the Space Shuttle, taken in April 1994Visibility from the moon
Popular beliefs ranging from Ripley's Believe It or Not!'s cartoons from 1930s, which claimed that the Great Wall is "the mightiest work of man, the only one that would be visible to the human eye from the moon," to Richard Halliburton's 1938 book Second Book of Marvels which makes a similar claim, have persisted, assuming urban legend status, and sometimes even appearing in school textbooks. Arthur Waldron, author of The Great Wall of China: From History to Myth, has speculated that the belief might go back to the fascination with the "canals" once believed to exist on Mars.
One of the earliest known references to this myth appears in a letter written in 175 by the English antiquary William Stukeley. Stukeley wrote that, "This mighty wall of four score miles in length (Hadrian's Wall) is only exceeded by the Chinese Wall, which makes a considerable figure upon the terrestrial globe, and may be discerned at the moon."

The Great Wall is a maximum 9.1 m (30 ft) wide and is about the same color as the soil surrounding it. Based on the optics of resolving power (distance versus the width of the iris: a few millimetres for the human eye, metres for large telescopes) only an object of reasonable contrast to its surroundings 70 miles or more in diameter (1 arc-minute) would be visible to the unaided eye from the moon, whose average distance from Earth is 384,393 km (238,857 miles). The apparent width of the Great Wall from the moon is the same as that of a human hair viewed from 2 miles away. To see the wall from the moon would require spatial resolution 17,000 times better than normal (20/20) vision.[11] Unsurprisingly, no lunar astronaut has ever claimed seeing the Great Wall from the moon.

Visibility from low earth orbit
A more controversial question is whether the Wall is visible from low earth orbit, i.e., an altitude of as little as 100 miles (160 km). NASA claims that it is barely visible, and only under nearly perfect conditions; it is no more conspicuous than many other man-made objects.[12] Other authors have argued that due to limitations of the optics of the eye and the spacing of photoreceptors on the retina, it is impossible to see the wall with the naked eye, even from low orbit, and would require visual acuity of 20/3 (7.7 times better than normal).

Anecdotal reports
Astronaut William Pogue thought he had seen it from Skylab but discovered he was actually looking at the Grand Canal of China near Beijing. He spotted the Great Wall with binoculars, but said that "it wasn't visible to the unaided eye." U.S. Senator Jake Garn claimed to be able to see the Great Wall with the naked eye from a space shuttle orbit in the early 1980s, but his claim has been disputed by several U.S. astronauts. Veteran U.S. astronaut Gene Cernan has stated: "At Earth orbit of 100 miles (160 km) to 200 miles (320 km) high, the Great Wall of China is, indeed, visible to the naked eye." Ed Lu, Expedition 7 Science Officer aboard the International Space Station, adds that, "it's less visible than a lot of other objects. And you have to know where to look."

Neil Armstrong stated about the view from Apollo 11: "I do not believe that, at least with my eyes, there would be any man-made object that I could see. I have not yet found somebody who has told me they've seen the Wall of China from Earth orbit. ...I've asked various people, particularly Shuttle guys, that have been many orbits around China in the daytime, and the ones I've talked to didn't see it."

Topographic maps put together showing the location of the eastern parts of the wall between the Yellow River and the Bohai Sea.In October 2003, Chinese astronaut Yang Liwei stated that he had not been able to see the Great Wall of China. In response, the European Space Agency (ESA) issued a press release reporting that from an orbit between 160 and 320 km, the Great Wall is visible to the naked eye. In an attempt to further clarify things, the ESA published a picture of a part of the “Great Wall” photographed from Space. However, in a press release a week later (no longer available in the ESA’s website), they acknowledged that the "Great Wall" in the picture was actually a river.

Leroy Chiao, a Chinese-American astronaut, took a photograph from the International Space Station that shows the wall. It was so indistinct that the photographer was not certain he had actually captured it. Based on the photograph, the China Daily later reported that the Great Wall can be seen from space with the naked eye, under favorable viewing conditions, if one knows exactly where to look.[14] However, the resolution of a camera can be much higher than the human visual system, and the optics much better, rendering photographic evidence irrelevant to the issue of whether it is visible to the naked eye.

The Millau Viaduct (French: le Viaduc de Millau, Occitan: lo Viaducte de Milhau) is an enormous cable-stayed road-bridge that spans the valley of the river Tarn near Millau in southern France. Designed by the structural engineer Michel Virlogeux and British architect Norman Foster, it is the tallest vehicular bridge in the world, with one mast's summit at 343 metres (1,125 ft) — slightly taller than the Eiffel Tower and only 38 m (125 ft) shorter than the Empire State Building. The viaduct is part of the A75-A71 autoroute axis from Paris to Montpellier. It was formally dedicated on 14 December 2004, inaugurated the day after and opened to traffic two days later. The bridge won the 2006 IABSE Outstanding Structure Award.[1]

Construction records
The bridge’s construction broke three world records:
The highest pylons in the world: pylons P2 and P3, 244.96 metres (803 ft 8 in) and 221.05 metres (725 ft 3 in) in height respectively, broke the French record previously held by the Tulle and Verrières Viaducts (141 m/460 ft), and the world record previously held by the Kochertal Viaduct (Germany), which is 181 metres (590 ft) at its highest;
The highest bridge tower in the world: the mast atop pylon P2 peaks at 343 metres (1,130 ft).
The highest road bridge deck in the world, 270 m (890 ft) above the Tarn River at its highest point. It is nearly twice as tall as the previous tallest vehicular bridge in Europe, the Europabrücke in Austria. It is slightly higher than the New River Gorge Bridge in West Virginia in the United States, which is 267 m (880 ft) above the New River. Only the bridge deck of the Royal Gorge Bridge in Colorado, United States (mainly a pedestrian bridge over the Arkansas River, occasionally also used by motor vehicles) is higher with 321 m (1,050 ft), and is considered the highest bridge in the world.

The Millau Viaduct is located on the territory of the communes of Millau and Creissels, France, in the département of Aveyron. Before the bridge was constructed, traffic had to descend into the Tarn River valley and pass along the route nationale N9 near the town of Millau, causing heavy congestion at the beginning and end of the July and August vacation season. The bridge now traverses the Tarn valley above its lowest point, linking two limestone plateau, the Causse du Larzac and the Causse Rouge, and is inside the perimeter of the Grands Causses regional natural park.

The bridge forms the last link of the A75 autoroute, (la Méridienne) from Clermont-Ferrand to Pézenas (to be extended to Béziers by 2010). The A75, with the A10 and A71, provides a continuous high-speed route south from Paris through Clermont-Ferrand to the Languedoc region and through to Spain, considerably reducing the cost of vehicle traffic travelling along this route. Many tourists heading to southern France and Spain follow this route because it is direct and without tolls for the 340 kilometres (210 mi) between Clermont-Ferrand and Pézenas, except for the bridge itself.

The Eiffage group, which constructed the viaduct, also operates it, under a government contract which allows the company to collect tolls for up to 75 years. The toll bridge costs €5.60 for light automobiles (€7.40 during the peak months of July and August).

North-South axes
The four route options for Perpignan–ParisAs of 2007[update], there are four north-south routes, or axes, traversing France:
In the east, the Paris-Lyon-Vallée du Rhône route using the A6 and A7 autoroutes;
In the west, the Paris-Bordeaux-Agen-Toulouse route using the A10 and A62 autoroutes;
Centrally, west of the Massif Central, the Vierzon-Limoges-Brive-Toulouse route using the A20;
Centrally, through the Massif central and using the Millau Viaduct, the Clermont-Ferrand-Béziers route using the A75.
A75 autoroute
Construction started in 1975 and was finished in 2004 when the Millau Viaduct went into service.
The new A75 autoroute, complementing the A71 from Orléans to Clermont-Ferrand, created a fourth route through France and has several advantages:
It relieves traffic congestion in the Rhone Valley which connects Northern Europe with Spain and Portugal, and allows holiday-makers to reach the Mediterranean quickly;
It also opens up the Massif Central and the town of Clermont-Ferrand to the south;
It enhances the French motorway network and, in a wider perspective, facilitates travel between Northern Europe and the Île de France on one hand, and on the other, Spain and the west Mediterranean region.
Bypassing Tarn at Millau
The Tarn flows from the east to the west of France, south of the Massif Central, bisecting the country's North-South axis.

For nearly thirty years prior to the construction of the Millau Viaduct, the A75 autoroute had remained unfinished. Before the bridge, a crossing of the River Tarn was provided by a bridge situated in the valley bottom, in the town of Millau. Millau was then known and dreaded as a ‘great black spot’ of motoring. Kilometres of congestion and hours of waiting to transit the town recurred each year with the great surge in traffic in summer months. These slowdowns meant that the advantages of the A75 were lost. The A75 was meant to be a positive example of spatial planning, a modern, direct highway entirely free along its 340 km (210 mi) length. As it was, the traffic from the autoroute brought pollution and danger to the town of Millau.

Design and construction of the bridge took a long time. In this region, climatic conditions are tough, with violent winds. Geological characteristics of the high plateaus of Larzac are peculiar, and, because the Tarn Valley is so deep, crossing is difficult. Different approaches were investigated, and all of them were found to be very technically demanding. Ten years of research and four years of implementation were required for completion of the Millau Viaduct.

Description
The Millau Viaduct consists of an eight-span steel roadway supported by seven concrete pylons. The roadway weighs 36,000 tonnes and is 2,460 m (8,100 ft) long, measuring 32 m (100 ft) wide by 4.2 m (14 ft) deep, making it the world's longest cable-stayed deck. The six central spans each measure 342 m (1,120 ft) with the two outer spans measuring 204 m (670 ft). The roadway has a slope of 3% descending from south to north, and curves in a plane section with a 20 km (12 mi) radius to give drivers better visibility. The pylons range in height from 77 m (250 ft) to 246 m (8
10 ft), and taper in their longitudinal section from 24.5 m (80 ft) at the base to 11 m (36 ft) at the deck. Each pylon is composed of 16 framework sections, each weighing 2,230 tons. These sections were assembled on site from pieces of 60 tons, 4 m (13 ft) wide and 17 m (56 ft) long, made in factories in Lauterbourg and Fos-sur-Mer by Eiffage. The pylons each support 97 m (320 ft) tall masts.

The pylons were assembled first, together with some intermediate temporary pylons which were in themselves a substantial construction project.

The entire length of deck surface (that is to say, the bridge itself, the roadway) was slid out across the pylons from both sides by hydraulic rams that moved the deck 600 mm every 4 minutes. Then the masts were erected on top of the pylons, connected to the deck and the temporary pylons removed.

Construction began on 10 October 2001 and was intended to take three years, but weather conditions put work on the bridge behind schedule. A revised schedule aimed for the bridge to be opened in January 2005. The viaduct was inaugurated by President Chirac on 14 December 2004 to open for traffic on 16 December, several weeks ahead of the revised schedule.

The construction of the bridge was depicted in an episode of the National Geographic Channel MegaStructures series, as well as Discovery Channel's Extreme Engineering.

Deck
The metallic deck, which appears very light despite its total mass of around 36,000 metric tons (40,000 short tons), is 2,460 m (8,100 ft) long and 32 m (100 ft) wide. It comprises eight spans. The six central spans measure 342 m (1,120 ft), and the two outer spans are 204 metres (670 ft). These are composed of 173 central box beams, the spinal column of the construction, onto which the lateral floors and the lateral box beams were welded. The central box beams have a 4 m (13 ft) cross-section and a length of 15–22 m (49-72 ft) for a total weight of 90 metric tons (99 short tons). The deck has an inverse airfoil shape, providing negative lift in strong wind conditions.

Masts
The seven masts, each 87 m (290 ft) high and weighing around 700 metric tons (770 short tons), are set on top of the pylons. Between each of them, eleven stays (metal cables) are anchored, providing support for the road deck.

Stays
Each mast of the viaduct is equipped with a monoaxial layer of eleven pairs of stays laid face to face. Depending on their length, the stays were made of 55 to 91 high tensile steel cables, or strands, themselves formed of seven strands of steel (a central strand with six intertwined strands). Each strand has triple protection against corrosion (galvanisation, a coating of petroleum wax and an extruded polyethylene sheath). The exterior envelope of the stays is itself coated along its entire length with a double helical weatherstrip. The idea is to avoid running water which, in high winds, could cause vibration in the stays and compromise the stability of the viaduct.
The stays were installed by the Freyssinet company.

surface
To allow for deformations of the metal deck under traffic, a special surface of modified bitumen was installed by research teams from Appia. The surface is somewhat flexible to adapt to deformations in the steel deck without cracking, but it must nevertheless have sufficient strength to withstand motorway conditions (fatigue, density, texture, adherence, anti-rutting, etc.). The "ideal formula" was found only after ten years of research.

Electrical installations
The electrical installations of the viaduct are impressive, in proportion to the immensity of the bridge. There are 30 km (19 mi) of high-current cables, 20 km (12 mi) of fibre optics, 10 km (6.2 mi) of low-current cables and 357 telephone sockets allowing maintenance teams to communicate with each other and with the command post. These are situated on the deck, on the pylons and on the masts.

As far as instrumentation is concerned, the viaduct is state of the art. The pylons, deck, masts and stays are equipped with a multitude of sensors. These are designed to detect the slightest movement in the viaduct and measure its resistance to wear-and-tear over time. Anemometers, accelerometers, inclinometers, temperature sensors are all used for the instrumentation network.

Twelve fibre optic extensometers were installed in the base of pylon P2. Being the tallest of all, it is therefore under the most intense stress. These sensors detect movements on the order of a micrometre. Other extensometers — electrical this time — are distributed on top of P2 and P7. This apparatus is capable of taking up to 100 readings per second. In high winds, they continuously monitor the reactions of the viaduct to extreme conditions. Accelerometers placed strategically on the deck monitor the oscillations that can affect the metal structure. Displacements of the deck on the abutment level are measured to the nearest millimetre. The stays are also instrumented, and their ageing meticulously analysed. Additionally, two piezoelectric sensors gather traffic data: weight of vehicles, average speed, density of the flow of traffic, etc. This system can distinguish between fourteen different types of vehicle.

The data is transmitted by an Ethernet network to a computer in the IT room at the management building situated near the toll plaza.

Toll plaza

The Gare de péage (toll plaza)The only toll plaza on the A75 autoroute, the bridge toll booths and the buildings for the commercial and technical management teams are situated 4 km (2.5 mi) north of the viaduct. The toll plaza is protected by a canopy in the shape of a leaf (formed from tendrilled concrete, using the ceracem process). Consisting of 53 elements (voussoirs), the canopy is 100 m (330 ft) long and 28 m (92 ft) wide. It weighs around 2,500 metric tons (2,800 short tons).

The toll plaza can accommodate sixteen lanes of traffic, eight in each direction. At times of low traffic volume, the central booth is capable of servicing vehicles in both directions. A car park and viewing station, equipped with public toilets, is situated each side of the toll plaza. The total cost was €20 million.

Service area
The Visitor Centre and Farm, Aire de Viaduc de MillauIn 2005 temporary provision had been made to access the viewing point from junction 45. By 2006, there were separate exits from both carriageways of the A75, to Aire de Viaduc de Millau. Here there are three separated car parks for northbound, southbound and non-motorway traffic so cross over is not possible. There is an exhibition centre, and the existing buildings of the Farm of Brocuejouls are being restored.

Statistics
2,460 m (8,071 ft): total length of the roadway
7: number of piers
77 m (253 ft): height of Pier 7, the shortest
343 m (1,125 ft): height of Pier 2, the tallest (245 m/804 ft at the roadway's level)
87 m (285 ft): height of a mast
154: number of shrouds
270 m (886 ft): average height of the roadway
4.20 m (13 ft 9 in): thickness of the roadway
32.05 m (105 ft 2 in): width of the roadway
85,000 m3 (111,000 cu yd): total volume of concrete used
290,000 metric tons (320,000 short tons): total weight of the bridge
10,000–25,000 vehicles: estimated daily traffic
€5.40–7.00: typical automobile toll, as of July 2007[update]
20 km (12 mi): horizontal radius of curvature of the road deck
[edit] Preliminary studies
[edit] Chronology
1987: Establishment of the first plans by CETE of Aix-en-Provence;
19 October 1991: Choice of the high crossing of the Tarn River by a structure of around 2,500 m (8,200 ft);
1993–1994: Separate consultations with seven architects and eight structural engineers;
1995–1996: Second definition study with five associated architect groups and structural engineers;
10 January 1995: Declaration of public interest;[2]
9 July 1996: The jury decides in favour of a cable-stayed design with multiple spans, as proposed by the Sogelerg consortium (Michel Virlogeux and Norman Foster);
20 May 1998: Decision to proceed by grant of contract;
8 June 2000: Launch of the contest for the construction contract, open to four consortia;
March 2001: Eiffage establishes the subsidiary Compagnie Eiffage du Viaduc de Millau (CEVM) and is declared winner of the contest and awarded the prime contract;
August 2001: The contract is alloted to Eiffage[3] ;
8 October 2001: Decree formally approving the grant of contract.[4]
[edit] Possible routes

Routes of the four projects of the A75 autoroute around MillauIn initial studies, four options were examined:
An option called Great Eastern (grand Est) ( yellow route ) passing east of Millau and crossing the valleys of the Tarn and Dourbie on two very high and long bridges (spans of 800 m/2,600 ft and 1,000 m/3,300 ft) whose construction was acknowledged to be problematic. This option would have allowed access to Millau only from the Larzac plateau using the long and tortuous descent from La Cavalerie. Although this option was shorter and better suited to the through traffic, it was abandoned because it did not serve the needs of Millau and its area satisfactorily.
An option called the Great Western (grand Ouest) ( black route ), longer than the eastern option by 12 km (7.5 mi), following the Cernon valley. Technically easier (requiring four viaducts), this solution was judged to have negative impacts on the environment, in particular on the picturesque villages of Peyre and Saint-Georges-de-Luzençon. More expensive than the preceding option, and serving the region badly, this option was also abandoned.
An option called near RN9 (proche de la RN9) ( red route ), would have served the town of Millau well, but presented technical difficulties and would have had a strong impact on existing or planned structures. This option was also abandoned.
An option called intermediate (médiane), west of Millau ( blue route ) had the blessing of local opinion, but presented geological difficulties, notably on the question of crossing the valley of the Tarn. Expert investigation concluded that these obstacles were not insurmountable.
The fourth option was selected by the ministerial decree on 28 June 1989.[5] It encompassed two possibilities:
the high solution, envisaging a 2,500 m (8,200 ft) viaduct more than 200 m (660 ft) above the river;
the low solution, descending into the valley and crossing the river on a 200 m (660 ft) bridge, then a viaduct of 2,300 m (7,500 ft) extended by a tunnel on the Larzac side.
After long construction studies by the Ministry of Public Works, the low solution was abandoned because it would have intersected the water table, had a negative impact on the town, cost more, and lengthened the driving distance.

The choice of the “high” solution was decided by ministerial decree on October 29 1991.[6]

After the choice of the high viaduct, five teams of architects and researchers worked on a technical solution. The concept and design for the bridge was devised by French designer Michel Virlogeux. He worked with the Dutch engineering firm ARCADIS, responsible for the structural engineering of the bridge.

Choosing the definitive route
Satellite image of the route before construction of the bridge.The "high solution" required the construction of a 2,500 m (8,200 ft) long viaduct. Obviously, this would be the crown jewel of the entire A75 autoroute project. From 1991 to 1993, the structures division of Sétra, directed by Michel Virlogeux, carried out preliminary studies and examined the feasibility of a single structure spanning the valley. Taking into account technical, architectural and financial issues, the Administration of Roads then opened the question for competition between structural engineers and architects to widen the search for realistic designs. By July 1993, 17 structural engineers and 38 architects presented themselves as candidates for the preliminary studies. With the assistance of a multidisciplinary commission, the Administration of Roads selected 8 structural engineers for technical study and 7 architects for the architectural study.

Choice of technical design
Simultaneously, a school of international experts representing a wide spectrum of expertise (technical, architectural and landscape), chaired by Jean-François Coste, was established to clarify the choices which had to be made. In February 1995, on the basis of proposals of the architects and structural engineers, and with support of the school of experts, five general designs were identified.

The competition was relaunched: five combinations of architects and structural engineers, drawn from the best candidates of the first phase, were formed to each conduct in-depth studies of one of the general designs. On 15 July 1996, Bernard Pons, minister of Public Works, announced the decision of the jury constituted of elected artists and experts and chaired by the director of highways, Christian Leyrit at the time. The solution of a cable-stayed bridge, presented by the structural engineering group Sogelerg, Europe Etudes Gecti and Serf and the architects Foster + Partners was declared the best.

Detailed studies were carried out by the successful consortium, steered by the highways authority until mid-1998. After wind tunnel tests, the shape of the road deck was altered and detailed corrections were made to the design of the pylons. When the details were eventually finalised, the whole design was approved in late 1998.

Contractors
Once the Ministry of Public Works had taken the decision to offer the construction and operation of the viaduct as a grant of contract, an international call for tenders was issued in 1999. Four consortia tendered:

Compagnie Eiffage du Viaduc de Millau (CEVM), led by Eiffage
a consortium led by the Spanish company Dragados, with Skanska (Sweden), and Bec (France)
Société du Viaduc de Millau, including the French companies ASF, Egis, GTM, Bouygues Travaux Publics, SGE, CDC Projets, Tofinso and the Italian company Autostrade
a consortium led by Générale Routière, with Via GTI (France) and Cintra, Nesco, Acciona et Ferrovial Agroman (Spain).
The Compagnie Eiffage du Viaduc de Millau, working with the architect Sir Norman Foster, was successful in obtaining the tender[7]. The fact that the government had already taken the design work to an advanced stage meant that the technical uncertainties were considerably reduced. A further advantage was that it made the process of negotiating the contract easier, reducing public expense and speeding up construction, while minimising such design work as remained for the contractor.

All the member companies of the Eiffage group had some role in the construction work. The construction consortium was made up of the Eiffage TP company for the concrete part, the Eiffel company for the steel roadway (Gustave Eiffel built the Garabit viaduct in 1884, a railway bridge in the neighboring Cantal département), and the ENERPAC company for the roadway's hydraulic supports. The engineering group Setec has authority in the project, with SNCF engineering having partial control.

Appia was responsible for the job of the bituminous coating on the bridge deck, and Forclum for electrical installations. Management was handled by Eiffage Concessions.
The only other business that had a notable role on the building site was Freyssinet, a subsidiary of the Vinci Group specialising in prestressing, which was entrusted with installing the cable stays and putting them under tension, while the prestress division of Eiffage was responsible for prestressing the pillar heads.

The steel deck and the hydraulic action of the deck (the technical solution that had been successful in the competition for the design of the metallic moving parts) were designed by the engineering firm Greisch (BEL) from [Liège] [Belgium]. They carried out the general calculations and the resistance calculations for winds of up to 225 km/h (140 mph).

The sliding shutter technology for the bridge piers came from PERI.

Costs and resources
The bridge's construction cost up to €394 million,[8] with a toll plaza 6 km (3.7 mi) north of the viaduct costing an additional €20 million. The builders, Eiffage, financed the construction in return for a concession to collect the tolls for 75 years, until 2080.[9] However, if the concession is very profitable, the French government can assume control of the bridge in 2044.

The project required about 127,000 cubic metres (166,000 cu yd) of concrete, 19,000 metric tons (21,000 short tons) of steel for the reinforced concrete, and 5,000 metric tons (5,500 short tons) of pre-stressed steel for the cables and shrouds. The builder claims that the bridge's lifetime will be at least 120 years.

Opposition
Numerous organizations opposed the project, including the WWF, France Nature Environnement, the national federation of motorway users, and Environmental Action. Opponents put forward several arguments:

The westernmost route would be better, longer by three kilometres but a third of the cost with its three more conventional structures.
The objective of the viaduct would not be achieved; because of the toll, the viaduct would be little used and the project would not solve Millau's congestion problems.
The project would never break even; toll income would never amortise the initial investment and the contractor would have to be supported by subsidies.
The technical difficulties were too great and the bridge would be dangerous and unsustainable; the pylons, sitting on the shale of the Tarn Valley, would not support the structure adequately.
The viaduct represented a detour, reducing the number of visitors passing through Millau and slowing its economy.
Construction
Project timeline
The viaduct under construction, seen from the south in early 200416 October 2001: work begins
14 December 2001: laying of the first stone
January 2002: laying pier foundations
March 2002: start of work on the pier support C8
June 2002: support C8 completed, start of work on piers
July 2002: start of work on the foundations of temporary, height adjustable roadway supports
August 2002: start of work on pier support C0
September 2002: assembly of roadway begins
November 2002: first piers complete
25 February–26 February 2003: laying of first pieces of roadway
November 2003: completion of the last piers (Piers P2 at 245 m (800 ft) and P3 at 221 m (730 ft) are the highest piers in the world.)
28 May 2004: the pieces of roadway are several centimetres apart, their juncture to be accomplished within two weeks
2nd half of 2004: installation of the pylons and shrouds, removal of the temporary roadway supports
14 December 2004: official inauguration
16 December 2004: opening of the viaduct, ahead of schedule
10 January 2005: initial planned opening date
[edit] Pylons and abutments
Two weeks after the laying of the first stone on 14 December 2001, the workers started to dig the deep shafts. There were 4 per pylon; 15 m (49 ft) deep and 5 m (16 ft) in diameter, assuring the stability of the pylons. At the bottom of each pylon, a tread of 3–5 m (10-16 ft) in thickness was installed to reinforce the effect of the deep shafts. The 2,000 m3 (2,600 cu yd) of concrete necessary for the treads was poured at the same time.

In March 2002, the pylons emerged from the ground. The speed of construction then rapidly increased. Every three days, each pylon increased in height by 4 m (13 ft). This performance was mainly due to sliding shuttering. Thanks to a system of shoe anchorages and fixed rails in the heart of the pylons, a new layer of concrete could be poured every 20 minutes.

Rolling out of the deck
The bridge deck was constructed on land at the ends of the viaduct and rolled lengthwise from one pylon to the next, with eight temporary towers providing additional support. The movement was accomplished by a computer-controlled system of pairs of wedges under the deck; the upper and lower wedges of each pair pointing in opposite directions. These were hydraulically operated, and moved repeatedly in the following sequence:

The lower wedge slides under the upper wedge, raising it to the roadway above and then forcing the upper wedge still higher to lift the roadway.
Both wedges move forward together, advancing the roadway a short distance.
The lower wedge retracts from under the upper wedge, lowering the roadway and allowing the upper wedge to drop away from the roadway; the lower wedge then moves back all the way to its starting position. There is now a linear distance between the two wedges equal to the distance forward the roadway has just moved.
The upper wedge moves backward, placing it further back along the roadway, adjacent to the front tip of the lower wedge and ready to repeat the cycle and advance the roadway by another increment.
[edit] Erection of masts
The mast pieces were driven over the new deck, welded together and erected on top of the pylons. The stays connecting the masts and the deck were installed, and the temporary pylons were removed.

Impact and events
Pedestrian sporting events
Unusually for a bridge closed to pedestrians, a run took place in 2004 and another on 13 May 2007:

December 2004 - 19,000 walkers and runners of the Three Bridge Walk had the privilege of crossing the bridge deck for the first time, but the walk was not authorised to go further than pylon P1; the bridge was still closed to traffic.
13 May 2007 - 10,496 runners took the departure of the race which from Place de Mandarous, in the centre of Millau, to the southern end of the viaduct. After starting on the northern side, they crossed the viaduct then retraced their steps. Total distance: 23.7 km (14.7 mi).
Famous visitors
During construction, various personalities flocked to the bridge.[10] Amongst those:

Jacques Chirac for the opening ceremony 14 December 2004;
The Duke of Edinburgh (28 May 2004);
José Bové (30 April 2004);
Jean-Pierre Raffarin (7 April 2004);
Gilles de Robien (24 January 2003 and 14 December 2004);
Norman Foster (17 October 2003 and 14 December 2004);
Dominique Bussereau (29 September 2003);
Henri Salvador (in 2002);
Roselyne Bachelot-Narquin (October 2002);
Jean-Claude Gayssot (14 December 2001).
Miscellanea
In 2004, a fire started on the slope of causse rouges because of a spark originating from a welder. Some trees were destroyed.
The speed limit on the bridge was reduced from 130 km/h (81 mph) to 110 km/h (68 mph) because of traffic slowing down, due to tourists taking pictures of the bridge from the vehicles. Shortly after the bridge opened to traffic, passengers were stopping on the hard shoulder to admire the landscape and the bridge itself.
A stamp was designed by Sarah Lazarevic to commemorate the opening of the crossing.
The Chinese transport minister at the time visited the bridge on the first anniversary of its opening. The commission was impressed by the technical prowess of the bridge’s immense construction, but also by the legal and financial assembly of the viaduct. However, according to the minister, he did not envisage building a counterpart in People's Republic of China.
The cabinet of the governor of California Arnold Schwarzenegger, who envisaged the construction of a bridge in San Francisco Bay, asked the council of the town hall of Millau about the popularity of the construction of the viaduct.[2]
This bridge was featured in a scene of Mr. Bean's Holiday.
The hosts of the British motoring show Top Gear featured the bridge during Season 7, when they took a Ford GT, Pagani Zonda, and Ferrari F430 spyder on a road trip across France to see the newly completed bridge.