On Tuesday, the Eiffel Tower celebrated the 125th anniversary of its opening, more than two years after construction began. In honor of this milestone, Business Insider shared 13 facts about the Parisian landmark: For instance, at the time it was built, the tower was the tallest building in the world, a record it kept through 1930. Created as the entrance to the 1889 World's Fair, the Eiffel Tower is the most visited paid monument in the world. And it isn't just one color: Gustave Eiffel's masterwork is darker at the top and becomes lighter towards the bottom. Speaking of paint, every seven years, 50 to 60 tons of paint are applied to protect the tower — which was only meant to stand for 20 years — from rust. Read the rest of the facts here.