Extermination Camps(Vernichtungslager), Nazi camps in Poland in which millions of Jews were murdered as part of the "Final Solution", as well as hundreds of thousands of Roma (Gypsies), non-Jewish Poles and Soviet prisoners of war.
The 6 extermination camps were Auschwitz-Birkenau, Belzec, Chelmno, Majdanek, Sobibor and Treblinka. The purpose of these six camps was the systematic murder of human beings and the disposal of their bodies. Killing was done in a factory-like manner by poison gas in gas chambers or gas vans. The bodies were buried in mass graves or burned. The overwhelming majority of victims in these 6 camps were Jews.
Sources: Encyclopedia of the Holocaust; USHMM, Historical Atlas of the Holocaust.