Art theft, some might say, is the thinking man's crime.
First: there's the knowledge. The background in art history and antiques dealer-awareness required to pick the right target.
Then: there's the plotting; getting past gallery staff with a six foot canvas is harder than you might think.
Thirdly: there's the huge financial reward that comes if you get away with it. It's little wonder art theft has been central to some of the best thriller films out there.
While, as our gallery shows below, some of the most famous paintings in the world have been returned to the walls they were pinched from, others never have - with little clues as to their whereabouts.
So, next time you see that print of a Rembrandt self-portrait, you might want to double-check it actually is a print...