The city gave the Eiffel Tower 20 years, then meant to take it down.
Stand underneath and you are standing under a temporary structure. The tower went up as the entrance arch to the world’s fair of 1889, and Gustave Eiffel’s agreement with the city ran for 20 years. At the end of 1909 the thing became the property of Paris, which was entitled to take it apart and sell the iron for scrap.
What saved it was not beauty. Beauty was the argument against it: writers and painters had signed a public protest while it was still going up. What saved it was that the army found a use for the top. From 1903 the officer Gustave Ferrié was allowed to run wireless telegraphy aerials from the tower, with Eiffel paying for the experiments himself and making very sure the results were known. A permanent radio station followed.
A 300-metre aerial in the middle of the capital was worth more standing than flattened, and the demolition quietly stopped being discussed. Nobody in the crowd in 1889 was told they were looking at something permanent. They weren’t.
Source note: the tower’s own history pages at toureiffel.paris, on Eiffel’s 20-year concession and the wireless work begun in 1903.


