The Holocaust (from the Greek ὁλόκαυστος holókaustos: hólos, “whole” and kaustós, “burnt”), also referred to as the Shoah (Hebrew: השואה, HaShoah, “the catastrophe”), was a genocide in which some six million European Jews were killed by Adolf Hitler’s Nazi Germany, and the World War II collaborators with the Nazis. The victims included 1.5 million children, and represented about two-thirds of the nine million Jews who had resided in Europe. A broader definition of the Holocaust includes non-Jewish victims of the Nazi campaign of mass murder, based on biological factors, such as the Romani, and the Aktion T4 patients who were mentally and physically disabled.
From 1941 to 1945, Jews were systematically murdered in the deadliest genocide in history, which was part of a broader aggregate of acts of oppression and killings of various ethnic and political groups in Europe. Under the coordination of the SS, with directions from the highest leadership of the Nazi Party, every arm of Germany’s bureaucracy was involved in the logistics and the carrying out of the mass murder. Killings took place throughout German-occupied Europe, as well as within Nazi Germany, and across all territories controlled by its allies. Other victims of Nazi crimes included ethnic Poles and other Slavs, Soviet citizens and Soviet POWs, communists, homosexuals, Freemasons, Jehovah’s Witnesses, and others. Some 42,500 detention facilities were utilized in the concentration of victims for the purpose of gross violations of human rights. Over 200,000 people are estimated to have been Holocaust perpetrators.
The persecution was carried out in stages, culminating in the policy of extermination of European Jews termed the “Final Solution to the Jewish Question” (die Endlösung der Judenfrage). Following Hitler’s rise to power, the German government passed laws to exclude Jews from civil society, most prominently the Nuremberg Laws of 1935. Starting in 1933 the Nazis began to establish a network of concentration camps. After the outbreak of war in 1939 both German and foreign Jews were herded into wartime ghettos. In 1941, as Germany began to conquer new territory in the East, all anti-Jewish measures radicalized. Specialized paramilitary units called Einsatzgruppen murdered around two million Jews in mass shootings actions in less than a year. By mid-1942, victims were being regularly transported by freight trains to extermination camps where, if they survived the journey, most were systematically killed in gas chambers. This continued until the end of World War II in Europe in April–May 1945.
Jewish armed resistance was limited. The most notable exception was the Warsaw Ghetto uprising of 1943, when thousands of poorly-armed Jewish fighters held the Waffen-SS at bay for four weeks. An estimated 20,000–30,000 Jewish partisans actively fought against the Nazis and their collaborators in Eastern Europe. French Jews took part in the French Resistance, which conducted a guerilla campaign against the Nazis and Vichy French authorities. Over a hundred armed Jewish uprisings took place.
The use of extermination camps (also called “death camps”) equipped with gas chambers for the systematic mass extermination of peoples was an unprecedented feature of the Holocaust. These were established at Auschwitz, Belzec, Chełmno, Jasenovac, Majdanek, Maly Trostenets, Sobibór, and Treblinka. They were built for the systematic purpose of killing millions, primarily by gassing, but also by execution and extreme work under starvation conditions. Stationary facilities built for the purpose of mass extermination resulted from earlier Nazi experimentation with poison gas during the secret Action T4 euthanasia programme against mental patients.