In the past few years, more and more art museums have grown concerned about the presence of art within their collections that may have been seized by Nazis during the reign of the Third Reich. Not surprisingly, the Metropolitan Museum of Art has led the way in providing detailed information about the provenance of works of art in their holdings, particularly those with gaps in their history of ownership and items of Judaica. Given these circumstances, the Provenance Research Project allows users to view a variety of lists of artwork, including those seized by the Nazis during the Holocaust and returned to their rightful owners. For those looking for other works, there is a list of 449 European paintings with incomplete provenance for the Nazi era, along with online images, a description of the work, and its ownership history.