With the German invasion of the Soviet Union in June 1941, the extermination of European Jewry at killing sites began. Initially it was characterized by concentrated actions of mobile death squads, including: the operational divisions (Einsatzgruppen), German police units and local collaborators, in conjunction with the active assistance of the German army (the Wehrmacht). These units accompanied the invading forces into the Soviet Union, officially for the purpose of eliminating enemies of the regime - primarily leaders of the Communist party. In practice, the first few weeks saw these forces engaged in the mass murder of Jewish men, under the pretext of anti-partisan action. Within a short time, the acts of murder were extended to include women and children too, and were essentially the systematic extermination of the Jewish communities of Poland, the Soviet Union, Yugoslavia, Romania, Slovakia and others.
The death squads committed the acts of murder in the following manner: immediately after the German army conquered an area, the local Jewish community was gathered at a specific place such as the synagogue, prison or graveyard. They were led to a pre-arranged killing site, usually a natural valley, a specially prepared excavation, or existing pits such as anti-tank trenches, or pits for fuel tanks. These sites were located, for the most part, near the Jewish neighborhoods. The Jews were brought there on foot or by vehicle.
The Jewish victims were usually forced to undress and were then led to the pits, where they were shot. On this final passage, the Jews were continually abused. Some of them were held in the concentration areas for many hours, even days, with no food or water. En route they were beaten, often by their own neighbors who tried to plunder the valuables they were carrying. At the killing sites themselves the humiliation and abuse of the masses of naked men, women and children continued. In some cases the victims were forced to dig their own graves. Furthermore, some of the injuries did not cause the immediate death of the victims – many of whom suffered for many hours after being shot. Some were even buried alive.
Tens of thousands of German soldiers, as well as collaborators of various nationalities, took an active part in the murder. Many others helped gather the Jews and lead them to their deaths. Moreover, members of the local community and soldiers from different units often came to the killing sites in order to watch the mass executions, which at times lasted for days.
As of fall 1943, following the advance of the allied forces, the Germans started trying to conceal the murders. Prisoners, mostly Jews, were forced to dig up the mass graves and burn the remains of the corpses. When they had completed destroying the evidence they, in turn, were murdered. In a number of cases some prisoners managed to escape, and their testimony provides evidence of the extent of the murders and the German cruelty.
The larger killing sites, which became the graves for tens of thousands of people, include the Ninth Fort - a fortress near Kovna where around 50,000 Lithuanian and German Jews were murdered, Ponary - a vacation area near Vilna, to which some 70,000 Lithuanian Jews were taken, and Babi Yar - a riverbed on the outskirts of Kiev where 100,000 people, mostly Jews but also gypsies and Soviet prisoners, were murdered. In addition to these sites, which have been well publicized and commemorated, countless smaller places exist, where hundreds or thousands were murdered. In all, more than 2 million Jews were murdered at killing sites.