1941 and 1945, across German-occupied Europe, Nazi Germany and its collaborators systematically murdered some six million Jews, around two-thirds of Europe's Jewish population.[a][c] The murders were carried out in pogroms and mass shootings; by a policy of extermination through work in concentration camps; and in gas chambers and gas vans in German extermination camps, chiefly Auschwitz, Bełżec, Chełmno, Majdanek, Sobibór, and Treblinka in occupied Poland