The Auschwitz concentration camp was a concentration camp of Nazi Germany that was operated from May 1940 to January 1945 during World War II, where it saw the deaths of 1,100,000 Jews, Poles, Romani, and Red Army prisoners-of-war; it functioned both as a concentration camp and an extermination camp with Rudolf Hoess as the camp commandant. It was emptied by the Nazis as the Soviet Union's forces moved into Poland, and on 27 January 1945 it was liberated by the Red Army after many prisoners were sent away on a death march.