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
Eiffel Tower first level. The layout of both first and second levels was modified, with the space available for visitors on the second level. The original lift in the south pillar was removed 13 years later. On 19 October 1901, Alberto Santos-Dumont, flying his No.6 airship, won a 100,000-franc prize offered by Henri Deutsch de la Meurthe for the first person to make a flight from St. Cloud to the Eiffel Tower and back in less than half an hour. Many innovations took place at the Eiffel Tower in the early 20th century. In 1910, Father Theodor Wulf measured radiant energy at