The Holocaust: The first mass killings of Jews began at Belzec extermination camp in occupied Poland, the first of the Operation Reinhard camps to begin operation.

The Holocaust, known in Hebrew as the Shoah, was the genocide of European Jews during World War II. From 1941 to 1945, Nazi Germany and its collaborators systematically murdered some six million Jews across German-occupied Europe, around two-thirds of Europe's Jewish population. The murders were committed primarily through mass shootings across Eastern Europe and poison gas chambers in extermination camps, chiefly Auschwitz-Birkenau, Treblinka, Belzec, Sobibor, and Chełmno in occupied Poland. Separate Nazi persecutions killed millions of other non-Jewish civilians and prisoners of war (POWs); the term Holocaust is sometimes used to include the murder and persecution of non-Jewish groups.

Belzec was a Nazi German extermination camp in occupied Poland. It was built by the SS for the purpose of implementing the secretive Operation Reinhard, the plan to murder all Polish Jews, a major part of the "Final Solution", the overall Nazi effort to complete the genocide of all European Jews. Before Germany's defeat put an end to this project more than six million Jews had been murdered in the Holocaust. The camp operated from 17 March 1942 to the end of June 1943. It was situated about 500 m (1,600 ft) south of the local railroad station of Bełżec, in the new Lublin District of the General Government territory of German-occupied Poland. The burning of exhumed corpses on five open-air grids and bone crushing continued until March 1943.

The General Government, formally the General Governorate for the Occupied Polish Region, was a German zone of occupation established after the invasion of Poland by Nazi Germany, Slovakia and the Soviet Union in 1939 at the onset of World War II. The newly occupied Second Polish Republic was split into three zones: the General Government in its centre, Polish areas annexed by Nazi Germany in the west, and Polish areas annexed by the Soviet Union in the east. The territory was expanded substantially in 1941, after the German Invasion of the Soviet Union, to include the new District of Galicia. The area of the Generalgouvernement roughly corresponded with the Austrian part of the Polish–Lithuanian Commonwealth after the Third Partition of Poland in 1795.