The killings continued uninterrupted. On 12 October 1941, in Stanisławów, some 10,000–12,000 Jewish men, women, and children were shot at the Jewish cemetery by the German uniformed SS-men and Ukrainian Auxiliary Police during the so-called "Bloody Sunday" (de). The shooters began firing at 12 noon and continued without stopping by taking turns. There were picnic tables set up on the side with bottles of vodka and sandwiches for those who needed to rest from the deafening noise of gunfire. It was the single largest massacre of Polish Jews in Generalgouvernement prior to mass gassings of Aktion Reinhard, which commenced at Bełżec in March 1942. Notably, the extermination operations in Chełmno had begun on 8 December 1941, one-and-a-half month before Wannsee, but Chełmno – located in Reichsgau Wartheland – was not a part of Reinhard, and neither was Auschwitz-Birkenau functioning as an extermination center until November 1944 in Polish lands annexed by Hitler and added to Germany proper.
How, when, and why the Nazis’ decision to exterminate Europe’s Jews was made remains one of the most vexed and disputed of all important questions concerning the Holocaust. There was not simply an order from Hitler commanding the killing of the Jews, and there is general agreement that the genocide evolved in stages, steadily becoming more comprehensive. The Origins of the Final Solution by the universally respected historian Christopher R. Browning, now at the University of North Carolina at Chapel Hill, is a magisterial examination of this subject in the wider context of the overall evolution of Nazi policy towards the Jews between the outbreak of the Second World War in September 1939 and the opening of the first extermination camps early in 1942.
^ Bradley F. Smith & Agnes Peterson (1974), Heinrich Himmler. Speeches Frankfurt/M., p. 169 f. OCLC 1241890; "Himmler's Speech in Posen on 6 October 1944". Holocaust Controversies Reference Section. Archived from the original on 27 January 2016. Retrieved 28 February 2015.; also (with differing translation) in "Heinrich Himmler". United States Holocaust Memorial Museum. Archived from the original on 14 December 2013. Retrieved 28 February 2015.
Here over an acre of ground lay dead and dying people. You could not see which was which. ... The living lay with their heads against the corpses and around them moved the awful, ghostly procession of emaciated, aimless people, with nothing to do and with no hope of life, unable to move out of your way, unable to look at the terrible sights around them ... Babies had been born here, tiny wizened things that could not live. ... A mother, driven mad, screamed at a British sentry to give her milk for her child, and thrust the tiny mite into his arms. ... He opened the bundle and found the baby had been dead for days. This day at Belsen was the most horrible of my life.
Mengele joined the Nazi Party in 1937 and the Schutzstaffel (SS; protection squadron) in 1938. He received basic training in 1938 with the Gebirgsjäger (light infantry mountain troop) and was called up for service in the Wehrmacht (Nazi armed forces) in June 1940, some months after the outbreak of World War II. He soon volunteered for medical service in the Waffen-SS, the combat arm of the SS, where he served with the rank of SS-Untersturmführer (second lieutenant) in a medical reserve battalion until November 1940. He was next assigned to the SS-Rasse- und Siedlungshauptamt (SS Race and Settlement Main Office) in Poznań, evaluating candidates for Germanization.