The Louvre fills a former royal palace, and its scale is the first thing you meet. Corridors run for miles, tens of thousands of works reach from Egyptian mummies to Renaissance masters, and a single day barely scratches one wing. You enter through I. M. Pei's glass pyramid into a light-filled hall, then choose a direction. Most visitors funnel toward a small guarded painting behind glass, where a scrum of raised phones surrounds the Mona Lisa. Walk away from her and the corridors empty out: a gallery of Mesopotamian carvings with nobody in it, the Winged Victory at the head of her staircase, the Egyptian rooms most people never reach.
It began as a fortress, and its medieval moat and keep still stand in the basement beneath the crowds. Kings enlarged the building wing by wing across nearly seven centuries, turning a defensive castle into a sprawling palace, until the Revolution flung its doors open in 1793 and made the nation's treasures public. Pei's pyramid was bitterly opposed when it went up and now marks the museum's heart. It was sized for four million visitors a year and takes nine, so a second entrance is being cut beneath the east colonnade, due to open by 2031.