The Holocaust was a genocide during World War II in which Nazi Germany, aided by its collaborators, systematically murdered approximately 6 million European Jews, around two-thirds of the Jewish population of Europe, between 1941 and 1945. The Nazis also targeted other groups such as the Romani people, Slavs, Communists, homosexuals and disabled people. Millions of others were imprisoned and suffered horrific abuse and neglect in ghettos and concentration camps.