“THE Mona Lisa’s lure is so strong that Louvre Museum officials find it wise to keep her safely stowed behind bulletproof glass. She is let out of her protective cage once a year, for a whiff of fresh air. And this is when many a researcher would love to get their hands on Leonardo da Vinci’s most famous muse, in order to find out more about how she was painted.”

via http://www.economist.com/node/16635928?story_id=16635928&fsrc=nlw|hig|07-22-2010|editors_highlights.