Identical to some other valuable objects, famous works of art are routinely targeted by thieves, and as soon as they've been stolen, they are rarely recovered. Rembrandt completed an enormous collection of self-portraits, nevertheless it was his 1630 portrait of himself in a beret and gathered shirt that was targeted by thieves in 2000. The painting, finished on a sheet of copper, was recovered in 2005 and is valued at $37 million. Monet did a series of well-known paintings of London bridges. A...