The genocide was organised and executed by Heinrich Himmler and Reinhard Heydrich. The records of the Wannsee Conference, held on 20 January 1942 and led by Heydrich, with fifteen senior Nazi officials participating, provide the clearest evidence of systematic planning for the Holocaust. On 22 February, Hitler was recorded saying, "we shall regain our health only by eliminating the Jews". Similarly, at a meeting in July 1941 with leading functionaries of the Eastern territories, Hitler said that the easiest way to quickly pacify the areas would be best achieved by "shooting everyone who even looks odd". Although no direct order from Hitler authorising the mass killings has surfaced, his public speeches, orders to his generals, and the diaries of Nazi officials demonstrate that he conceived and authorised the extermination of European Jewry. During the war, Hitler repeatedly stated his prophecy of 1939 was being fulfilled, namely, that a world war would bring about the annihilation of the Jewish race. Hitler approved the Einsatzgruppen—killing squads that followed the German army through Poland, the Baltic, and the Soviet Union—and was well informed about their activities. By summer 1942, Auschwitz concentration camp was expanded to accommodate large numbers of deportees for killing or enslavement. Scores of other concentration camps and satellite camps were set up throughout Europe, with several camps devoted exclusively to extermination.