From 1933 through the end of World War II in 1945, the Nazi regime systematically pillaged cultural property and artworks throughout continental Europe. Some of their loot was sold to fund Nazi-related activities; some became the property of senior party officials. Other pieces were destroyed. After the war, tens of thousands of confiscated objects were recovered by the Allies, but that was only a portion of the works stolen. Although exhaustive efforts were made to return these objects to their rightful owners, many works of art never found their way home.
To this day, museums and individual collectors still struggle to verify the proper ownership of works of art that changed hands during these years.