The Louvre started as a fortress

A closer look

Before it was the elegant home to the Mona Lisa and hordes of camera-wielding tourists, the Louvre was built to keep people out, not invite them in. Originally constructed in the 12th century as a rugged, heavily fortified castle to protect Paris from Viking raids, it was slowly entirely remodeled into a lavish royal palace. You can still see the grim, dark medieval foundation stones in the basement, stubbornly hiding beneath centuries of polished fine art.