Le champ-de-Mars, vu de la nacelle du ballon captif Lachambre 2

Eiffel Tower was envisioned as a centerpiece for the 1889 Exposition Universelle, a world's fair to celebrate the centennial of the French Revolution. Eiffel acknowledged that inspiration for a tower came from the Latting Observatory built in New York City in 1853. On 30 March 1885, Eiffel presented his tower design to the Société des Ingénieurs Civils. Little progress was made until 1886 when a budget for the exposition was passed and an open competition was held for a centerpiece to the exposition and decided that all the proposals except Eiffel's were either impractical or lacking in details. The proposed tower had been a subject of controversy. Prior to the Eiffel Tower's construction, no structure had ever been constructed to a height of 300 m, and many people believed it was impossible. Some of the protesters changed their minds when the tower was built; others remained unconvinced. The main structural work was completed at the end of March 1889. 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. The Eiffel Tower's lighting and sparkling lights are protected by copyright, so professional use of images of the Eiffel Tower at night requires prior authorization and may be subject to a fee.