On March 19, 1990, a rather daring and amazing art theft happened at the Isabella Stewart Gardner Museum in Boston. The take, now estimated at half a billion, has never been recovered, nor have the perpetrators ever been caught.

The rather curious conditions of Gardner’s will, however, insist that the museum be left in the precise configuration she chose; there were to be no new acquisitions, and no rotation of the art. Consequently, not only have the missing pieces not been replaced with other art; said pieces were also not even insured because, well, the trustees wouldn’t have been able to hang them.