Leni Riefenstahl had several successes at the Venice film festival. In 1932, the festival’s inaugural year, the German film-maker’s mystical mountain drama The Blue Light made the official selection. In 1934, she picked up a gold medal for Triumph of the Will, her chronicle of the Nazi party congress in Nuremberg. In 1938, 10 weeks before Kristallnacht, she won best foreign film with Olympia, a two-part documentary of the summer Olympics in Berlin that was commissioned and financed by the Nazi government, overseen by the Reich ministry of propaganda and enlightenment, and released on Adolf Hitler’s birthday. After the war,...