Eiffel Tower

The Eiffel Tower is a 19th century iron lattice tower located on the Champ de Mars in Paris that has become both a global icon of France and one of the most recognizable structures in the world. The Eiffel Tower, which is the tallest building in Paris, is the single most visited paid monument in the world; millions of people ascend it every year. Named after its designer, engineer Gustave Eiffel, the tower was built as the entrance arch for the 1889 Worlds Fair.

The tower stands at 324 m or 1,063 ft tall, about the same height as an 81-story building. It was the tallest structure in the world from its completion until 1930, when it was eclipsed by the Chrysler Building in New York City. Not including broadcast antennas, it is the second-tallest structure in France, behind the Millau Viaduct, completed in 2004. And while the Eiffel Tower is an iron structure, and weighs approximately 10,000 tonnes, it actually has a relatively low density, weighing less than a cylinder of air occupying the same dimensions as the tower.

The tower has three levels for visitors. Tickets can be purchased to ascend either on stairs or lifts to the first and second levels. The walk to the first level is over 300 steps, as is the walk from the first to the second level. The third and highest level is accessible only by lift. Both the first and second levels feature restaurants. The tower has become the most prominent symbol of both Paris and France, often in the establishing shot of movies set in the city.

Eiffel originally planned to build the tower in Barcelona, for the Universal Exposition of 1888, but those responsible at the Barcelona city hall thought it was a strange and expensive construction, which did not fit into design of the city. After the refusal of the Consistory of Barcelona, Eiffel submitted his draft to those responsible for the Universal Exhibition in Paris, where he would build his tower a year later, in 1889. The tower was inaugurated on 31 March 1889, and opened on 6 May. Three hundred workers joined together 18,038 pieces of puddled iron, using two and a half million rivets, in a structural design by Maurice Koechlin. The risk of accident was great, for unlike modern skyscrapers the tower is an open frame without any intermediate floors except the two platforms.

The metal structure of the Eiffel Tower weighs 7,300 tonnes while the entire structure including non-metal components is approximately 10,000 tonnes. Depending on the ambient temperature, the top of the tower may shift away from the sun by up to 18 cm or 7.1 in because of thermal expansion of the metal on the side facing the sun. As demonstration of the economy of design, if the 7300 tonnes of the metal structure were melted down it would fill the 125 metre square base to a depth of only 6 cm or 2.36 in, assuming a density of the metal to be 7.8 tonnes per cubic metre. The tower has a mass less than the mass of the air contained in a cylinder of the same dimensions that is 324 metres high and 88.3 metres in radius. The weight of the tower is 10,100 tonnes compared to 10,265 tonnes of air.

Maintenance of the tower includes applying 50 to 60 tonnes of paint every seven years to protect it from rust. More than 200,000,000 people have visited the tower since its construction in 1889, including 6,719,200 in 2006, making it the most visited paid monument in the world. The tower has two restaurants Altitude 95, on the first floor 311 ft or 95 m above sea level and the Jules Verne, an expensive gastronomical restaurant on the second floor, with a private lift. This restaurant has one star in the Michelin Red Guide. In January 2007, the multi-Michelin star chef Alain Ducasse was brought in to run Jules Verne.