Eiffel Tower was to be dismantled in 1909, when its ownership would revert to the City of Paris. The City had planned to tear it down (part of the original contest rules for designing a tower was that it should be easy to dismantle) but as the tower proved to be valuable for communication purposes, it was allowed to remain after the expiry of the permit. Eiffel made use of his apartment at the top of the tower to carry out meteorological observations, and also used the tower to perform experiments on the action of air resistance on falling bodies. For the
Gustave Eiffel Using this Eiffel definitely established that the air resistance of a body was very closely related to the square of the airspeed. He then built a laboratory on the Champ de Mars at the foot of the tower in 1905, building his first wind tunnel there in 1909. The wind tunnel was used to investigate the characteristics of the airfoil sections used by the early pioneers of aviation such as the Wright Brothers, Gabriel Voisin and Louis Blériot. Eiffel established that the lift produced by an airfoil was the result of a reduction of air pressure above the wing rather