The first Nazi concentration camp was built in 1933 at Dachau near Munich. Hitler ordered that Jews, Roma (Gypsies), Poles, political opponents, the handicapped, and others be interned in these camps. During the war they also served as slave labor camps. Death from brutality, hunger, and disease were very common in these camps.

The first extermination camps were built in 1941 at Treblinka and Sobibor. Those interned that seemed healthy sometimes worked as slave labor in concentration camps. The rest were murdered immediately, usually in gas chambers.