Eiffel Tower

When Gustave Eiffel built this thing for the 1889 World's Fair, over 300 prominent Parisians — including Guy de Maupassant and Alexandre Dumas fils — signed a petition calling it a "metallic horror" that would disfigure Paris. Maupassant reportedly ate lunch at the tower's restaurant every day, because it was the only place in Paris where he didn't have to look at it.

The tower was only meant to stand for twenty years, then be dismantled. Eiffel saved it by turning it into a giant radio antenna — by 1910 it was transmitting signals across the Atlantic, and during World War I it intercepted a German spy transmission that led to the arrest and execution of Mata Hari. When the Nazis occupied Paris in 1940, French resistance fighters cut the elevator cables so Hitler would have to climb the 1,665 stairs if he wanted to fly his flag from the top. He didn't.

The tower is repainted every seven years by hand, requiring 60 tonnes of paint. It's been eighteen different colors over the years, including yellow and reddish-brown, before settling on its current specially-mixed "Eiffel Tower Brown" — actually three slightly different shades, darker at the bottom and lighter at the top, to create the illusion of a uniform color against the sky.

What most visitors don't know: the tower grows. In summer heat, the iron expands and the tower can be up to 15 centimeters taller than in winter. Eiffel also built himself a private apartment at the very top, which he used to entertain guests including Thomas Edison. It's now open to visitors, furnished with wax figures of Eiffel and Edison sharing a conversation.