In the late 1930's the Nazis killed thousands of handicapped Germans by lethal injection and poisonous gas. After the German invasion of the Soviet Union in June 1941, mobile killing units following in the wake of the German Army began shooting massive numbers of Jews and Gypsies in open fields and ravines on the outskirts of conquered cities and towns. 

Eventually the Nazis created a more secluded and organized method of killing. Six extermination centers were established in occupied Poland where large-scale murder by gas and body disposal through cremation were conducted systematically. Victims were deported to these centers from Western Europe and from the ghettos in Eastern Europe which the Nazis had established. In addition, millions died in the ghettos and concentration camps as a result of forced labor, starvation, exposure, brutality, disease, and execution.

/Louis Bülow