The Nazis solved the logistical problem of disposing of the bodies of murdered Jews by building large crematoria, with furnaces to burn bodies. In one crematorium, over 750 bodies could be burned in a single day. The constant stream of smoke coming from the furnace chimneys was a reminder to the Jews kept as slave laborers of the fate of their family members, as well as what would befall them if they did not obey the guard’s commands.

Jews were also forced to work in the crematoria. Called Sonderkommando, these slave laborers had the terrible task of guiding unsuspecting Jews into the gas chambers for gassing, then disentangling the bodies and carrying them to the furnaces. Periodically, the Sonderkommando themselves were executed and replaced with new prisoners. Only a few managed to survive to the end of the war to give first-hand testimony about the Nazi killing apparatus.