How can museums show off their priceless art treasures while protecting them from growing incidents of vandalism? That debate was renewed this week after a man used black paint to scrawl on Mark Rothko's "Black on Maroon" painting at the Tate Modern in London.
Michelangelo's "David" was struck by a man wielding a hammer in 1991, breaking one of its toes.
A boy stuck chewing gum on Helen Frankenthaler's painting "The Bay" at the Detroit Institute of Arts in 2006.
Diego Velazquez's 'The Rokeby Venus' was attacked by a woman with a meat cleaver in 1914.
In 2007, a woman smeared red lipstick across an all-white painting by Cy Twombly.
The Rothko incident is just the latest in a long tradition of museum art vandalism. At the Clyfford Still Museum last December, a woman was caught urinating near a painting valued at over $30 million. At the Museum of Modern Art in New York in 1996, Canadian artist Jubal Brown intentionally vomited blue-colored foods on a Piet Mondrian painting.