Eiffel Tower bust of Gustave Eiffel by Antoine Bourdelle was unveiled at the base of the north leg on 2 May 1929. In 1930, the tower lost the title of the world's tallest structure when the Chrysler Building in New York City was completed. In 1938, the decorative arcade around the first level was removed. Upon the German occupation of Paris in 1940, the lift cables were cut by the French. The tower was closed to the public during the occupation and the lifts were not repaired until 1946. In 1940, German soldiers had to climb the tower to hoist a swastika-centered
Eiffel Tower gaps in the latticework. In the years since it was completed, engineers have put forward various mathematical hypotheses in an attempt to explain the success of the design. The most recent, devised in 2004 after letters sent by Eiffel to the French Society of Civil Engineers in 1885 were translated into English, is described as a non-linear integral equation based on counteracting the wind pressure on any point of the tower with the tension between the construction elements at that point. The Eiffel Tower sways by up to 9 centimetres (3.5 in) in the wind. When originally built, the first