Answer
Max Liebermann's art collection was looted by the Nazis after his wife's death in 1943. The collection was one of the most important in Germany and included works by Rembrandt, Rubens, and Van Dyck. The Nazis confiscated the collection and sold it off to fund their war effort. The collection was eventually returned to Liebermann's heirs after the war, but many of the works were lost or damaged.