The Eiffel Tower

The Eiffel Tower (French: Tour Eiffel, /tuʀ ɛfɛl/) is an iron tower built on the Champ de Mars beside the Seine River in Paris. The tower has become a global icon of France and is one of the most recognizable structures in the world.
Named after its designer, engineer Gustave Eiffel, the Eiffel Tower is the tallest building in Paris.[1] More than 200,000,000 have visited the tower since its construction in 1889,[2] including 6,719,200 in 2006,[3] making it the most visited paid monument in the world.[4][5] Including the 24 m (79 ft) antenna, the structure is 325 m (1,063 ft) high (since 2000), which is equivalent to about 81 levels in a conventional building.
Looking up at the Eiffel Tower.
At the time the tower was built many people were shocked by its daring shape. Eiffel was criticised for the design and accused of trying to create something artistic, or inartistic according to the viewer, without regard to engineering. Eiffel and his engineers, as renowned bridge builders however, understood the importance of wind forces and knew that if they were going to build the tallest structure in the world they had to be certain it would withstand the wind. In an interview reported in the newspaper Le Temps, Eiffel said:
“
Now to what phenomenon did I give primary concern in designing the Tower? It was wind resistance. Well then! I hold that the curvature of the monument's four outer edges, which is as mathematical calculation dictated it should be (...) will give a great impression of strength and beauty, for it will reveal to the eyes of the observer the boldness of the design as a whole.
”
—translated from the French newspaper Le Temps of 14 February 1887[11]
The shape of the tower was therefore determined by mathematical calculation involving wind resistance. Several theories of this mathematical calculation have been proposed over the years, the most recent is a nonlinear integral differential equation based on counterbalancing the wind pressure on any point on the tower with the tension between the construction elements at that point. That shape is exponential. A careful plot of the tower curvature however, reveals two different exponentials, the lower section having a stronger resistance to wind forces.[12][13]

Restaurants
The tower has two restaurants: Altitude 95, on the first floor (95 m, 311 ft, 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, a new multi-Michelin star chef Alain Ducasse was brought in to run Jules Verne.[15]