Laurence Rees: Auschwitz, like many institutions in the Third Reich, was hugely affected by the German invasion of the Soviet Union in June 1941. This camp may have been many, many miles behind the front line, but the increased radicalisation of the war in the east would leave its mark here.
Commentary: Hitler had said that the war against the Soviet Union would be a war of annihilation. And that description certainly applied to the fate of the Red Army prisoners the Germans captured. More than three million of them would die in German captivity of starvation or disease.
Words of Georgy Semenyak (Red Army soldier captured by the Germans): They never considered us to be humans. They could kill us or beat us up for no reason. Of course we were sure that it was unjust.
Commentary: And from the very first day of the war, the Germans particularly wanted to kill a distinct type of Soviet soldier – political officers, Commissars, like this man. And some of that killing would take place at Auschwitz.
Laurence Rees: Here on this very spot in the summer of 1941, in what were at the time gravel pits, Soviet Commissars, the political officers of the Red Army, were killed. They were brutally beaten, shot, or simply worked to death.
Commentary: Then a few weeks later in Block 11 at Auschwitz, the SS tried out a different method of killing.
Laurence Rees: In late August or early September 1941 the SS conducted a mass killing experiment here in the basement of Block 11. Several hundred Soviet prisoners of war and Polish prisoners taken from the nearby camp hospital were taken down here and imprisoned. And the SS attempted to kill them with the use of a powerful insecticide called Zyklon B.
Commentary: The prisoners died in agony here as the SS experimented with the dose of Zyklon B necessary to kill people rather than insects. And though the SS eventually decided that Zyklon B was an effective method of killing, it was clear that Block 11 was not the perfect place in Auschwitz to commit the crime, as the basement could not be completely sealed.
Laurence Rees: So they searched around the camp for another location to use as an improvised gas chamber. And they found it here in the camp crematorium.
Commentary: Soviet prisoners of war were amongst the first to die in this new gas chamber. A Polish Auschwitz prisoner witnessed the arrival of one group of Soviet POWs to be killed.
Words of Jerzy Bielecki (Auschwitz prisoner): Everyone was moaning and yelling because of the cold - it was an incredible sound, I never heard it before. Naked they enter the gassing chamber. It was a devilish, hellish image.
Commentary: But this was only to be the beginning of a regime of systematic mass murder at Auschwitz.