She was gone, and they didn't even miss her smile. Not until the next day, that is. In 1911, perhaps the most famous painting in the world, Da Vinci's "Mona Lisa", vanished from the Louvre Museum in Paris. It was taken on a Monday morning, but the alarm would not be raised until Tuesday at noon.

The resultant furor brought more than 150 Inspectors and policemen from La Sureté , the French National Police Force, rushing to the museum, where they promptly sealed all doors and grilled the staff and visitors. People were then allowed to go home, but the doors remained guarded, so that the police could make a sweep of the entire museum. It was a task that would take an entire week, because the Louvre covers a whopping 49 acres.

Despite a stringent investigation, and accusations hurled back and for by the museum and the police, few clues were found, and no trace of the painting. Parisians were at first shocked. It was impossible...wasn't it? Then their inherent sense of humor took over, with songs being sung in cafés, and naughty postcards and cartoons depicting Mona Lisa on vacation anywhere, but Paris.

Two years later, it would emerge that she had in fact, never left her home city. The Mona Lisa had been stored by the miscreant, in his apartment, only a couple of blocks from the museum.