Stolen Painting

With a value estimated in the hundreds of millions of dollars, the Mona Lisa is the world's most expensive painting ever stolen.
On August 21, 1911 ex Louvre employee Vincenzo Peruggia, who went by the name Leonardo Vincenzo, walked into an empty room, took the Mona Lisa off the wall, removed it from it's case in a stairwell and disappeared.
So impossible was the theft of the Mona Lisa that it was not discovered missing till the next day.
On December 11, 1913 the Mona Lisa was finally recovered after Leonardo Vincenzo tried to sell the painting to art dealer Alfredo Geri in Florence, Italy.