Today, a thick pane of bullet-proof security glass keeps artlovers a safe distance from the most famous painting in the world, Leonardo da Vinci’s “Portrait of Lisa Gherardini, Wife of Francesco Giacondo,” known in French as “La Joconde” and English as the “Mona Lisa.” But back in 1911, it was simply hung on the walls of the Musée du Louvre like any other canvas. That was until a former museum employee named Vincenzo Perrugia strolled into the gallery before opening hours on August 21, noticed the room was empty, took down the Mona Lisa and walked out of the Louvre with it under a painting smock. When the loss was finally noticed, the police were mystified. For two years, the whereabouts of the masterpiece was unknown, while French detectives made various wild guesses. (It had been stolen by the Germans. By anarchists. By evil geniuses. By lunatics.) They actually arrested the country’s top art critic, Guillame Apollinaire, then let him free. Then, out of the blue in 1913, an Italian art dealer in Florence was contacted by a man calling himself “Leonardo” who claimed to have the Mona Lisa and wanted to see it hang in the Uffizi, Italy’s top art museum. Although he found it hard to believe that the thief could be so reckless, the dealer tipped off the police and agreed to meet the strange Leonardo in a Milan hotel room. There, the nondescript fellow opened his suitcase, emptied out his socks and underwear, opened up a false bottom in the case to reveal the Mona Lisa – and was immediately arrested.