Operation Harvest Festival
Operation Harvest Festival (German: Aktion Erntefest) was the murder of up to 43,000 Jews at the Majdanek, Poniatowa and Trawniki concentration camps by the SS, the Order Police battalions, and the Ukrainian Sonderdienst on 3–4 November 1943. After a series of Jewish uprisings in ghettos and extermination camps, Heinrich Himmler ordered the murder of the remaining Jewish forced laborers in the Lublin District of German-occupied Poland.
Source: Wikipedia — Operation Harvest Festival (CC BY-SA 4.0)