A Vernichtungslager - extermination camp consisted of a complex of barracks, gas chambers, crematoria, and work centers specifically built for mass annihilation of undesired persons in Germany and in the conquered territories who were considered to be a threat to the Third Reich. For the most part these victims were Jews. But they also included Roma and Sinti - a.k.a. Gypsies, alleged mental defectives, some Slavic races, and other minorities. The major death camps, all located in Poland, were Auschwitz II - a.k.a. Birkenau, Belzec, Chelmno, Majdanek, Sobibor, and Treblinka. At its peak, Birkenau, the most notorious of all the extermination camps, housed over 100,000 people. Each gas chamber and crematorium, there were five, accommodated approximately two thousand victims at one time. In a day, 12,000 could be gassed and incinerated. Some able-bodied inmates initially were used in industrial slave labor battalions or in the task of genocide itself until they were virtually worked to death or knew too much and needed to be silenced. These unfortunate victims were exterminated also. Indeed, few victims are on record to ever have escaped or outlive these horror centers.

       In addition to the six major extermination centers where most western and central European Jews were murdered the Nazis also employed Einsatzgruppen - mobile killing units in eastern Europe. According to the historian Raul Hilberg, these mobile killing units were responsible for the murder of 1.4 million east-European Jews between 1941 and the end of the war, May 1945.