The Holocaust was the systematic persecution and murder of approximately six million Jews by the Nazi regime and its allies and collaborators. Between 1933-1945, Jews were segregated into ghettos, deported to concentration and extermination camps, and murdered en masse. In total, the Nazis established over 300 ghettos and camps across Europe where Jews and other victims lived in inhumane conditions before being transported to death camps to be killed in gas chambers or by other means. By 1945, around 90% of Europe's Jewish population had been killed under the Nazi "Final Solution" plan.