Isabella Stewart Gardner Museum Stolen Artwork

In March 1990, two thieves disguised as police officers stole 13 valuable works of art from the Isabella Stewart Gardner Museum in Boston. The theft, valued at $500 million, remains unsolved, and no artwork has been recovered. The museum offers a $10 million reward for information.
#12 I lived in Boston from 1984 to 1994, The Gardner Museum was always my favorite of the many Boston area museums. I've must've visited it at least 40 times. I was actually there the day before the robbery with my then girlfriend. I've always considered myself lucky to be one of the last people to see those stolen works in person.