Lost artworks are original pieces of art that credible sources indicate once existed but that cannot be accounted for in museums or private collections or are known to have been destroyed deliberately or accidentally, or neglected through ignorance and lack of connoisseurship. The US FBI maintains a list of "Top Ten Art Crimes"; a 2006 book by Simon Houpt and a 2018 book by Noah Charney and several other media outlets have profiled the most significant outstanding losses.