U.S. Museums Cope with Art Tainted by Nazi Looting by Guy Raz All Things Considered, October 10, 2006 · More than 600,000 pieces of artwork are believed to have been looted from private European collections by the Nazis between 1933 and 1945. Some of that art is in the United States. NPR's Guy Raz reports on the quandaries museums face as they investigate claims. Recently, Yale University reached a creative solution with an elderly man over a Courbet landscape valued in the millions.