Final answer:
Heinrich Himmler was the head of the SS and a central figure in the Nazi regime, playing a significant role in the Holocaust and enforcement of Nazi racial policies. He was responsible for the systematic murder of millions, including the execution of the 'Final Solution' and overseeing the construction of extermination camps like Auschwitz.
Step-by-step explanation:
Heinrich Himmler was a leading member of the Nazi Party and one of the primary architects of the Holocaust. During the Third Reich, Himmler held the position of Reichsführer-SS, head of the Schutzstaffel (SS), transforming it into a massive organization responsible for a wide range of atrocities. He was directly involved in the planning and execution of the genocide of millions of Jews, known as the "Final Solution". On July 17, 1941, after the invasion of the Soviet Union, Hitler granted Himmler broad authority over security matters in the occupied territory, directing him to eliminate any threats to German rule. In accordance with this mandate, Himmler coordinated the systematization of mass murder, including the development of gas vans and the construction of extermination camps like Auschwitz.