The Louvre, home to the Mona Lisa and other iconic works of art in Paris, closed abruptly Monday as the museum's staff staged an impromptu strike over large crowds of tourists and understaffing.

The Louvre has become a symbol of tourism pushed to its limits. As hot spots from Venice to the Acropolis race to curb crowds, the world's most iconic museum, visited by millions, is hitting a breaking point of its own.