Gas chamber in the context of "German invasion of the Soviet Union"

Operation Barbarossa was the invasion of the Soviet Union by Nazi Germany and several of its European Axis allies starting on Sunday, 22 June 1941, during World War II. More than 3.8 million Axis troops invaded the western Soviet Union along a 2,900-kilometer (1,800 mi) front, with the main goal of capturing territory up to a line between Arkhangelsk and Astrakhan, known as the A–A line. The attack became the largest and costliest military offensive in human history, with around 10 million combatants taking part in the opening phase and over 8 million casualties by the end of the operation on 5 December 1941. It marked a major escalation of World War II, opened the Eastern Front—the largest and deadliest land war in history—and brought the Soviet Union into the Allied powers.

The operation, code-named after the Holy Roman Emperor Frederick Barbarossa ("red beard"), put into action Nazi Germany's ideological goals of eradicating communism and conquering the western Soviet Union to repopulate it with Germans under Generalplan Ost, which planned for the removal of the native Slavic peoples by mass deportation to Siberia, Germanisation, enslavement, and genocide. The material targets of the invasion were the agricultural and mineral resources of territories such as Ukraine and Byelorussia and oil fields in the Caucasus. The Axis eventually captured five million Soviet Red Army troops on the Eastern Front and deliberately starved to death or otherwise killed 3.3 million prisoners of war, as well as millions of civilians. Mass shootings and gassing operations, carried out by German paramilitary death squads and collaborators, murdered over a million Soviet Jews as part of the Holocaust.

The sociology of punishment seeks to understand why and how we punish. Punishment involves the intentional infliction of pain and/or the deprivation of rights and liberties. Sociologists of punishment usually examine state-sanctioned acts in relation to law-breaking; for instance, why citizens give consent to the legitimation of acts of violence.

Two of the most common political and ethical motivations for formal punishment are utilitarianism and retributivism. Both these concepts have been articulated by law-makers and law-enforcers, but may be seen as descriptive rather than explanative. Sociologists note that although attempts of justification are made in terms of these principles, this does not fully explain why violent punitive acts occur. Social psychology and symbolic interactionism often inform theory and method in this area.

Nazi Germany used six extermination camps (German: Vernichtungslager), also called death camps (Todeslager), or killing centers (Tötungszentren), in Central Europe, primarily in German-occupied Poland, during World War II to systematically murder over 2.7 million people—mainly Jews—in the Holocaust. The victims of death camps were primarily murdered by gassing, either in permanent installations constructed for this specific purpose, or by means of gas vans. The six extermination camps were Chełmno, Bełżec, Sobibor, Treblinka, Majdanek and Auschwitz-Birkenau. Extermination through labour was also used at the Auschwitz and Majdanek death camps. Millions were also murdered in concentration camps, in the Aktion T4, or directly on site. Additionally, camps operated by Nazi allies have also been described as extermination or death camps, most notably the Jasenovac concentration camp in the Independent State of Croatia.

The National Socialists made no secret of the existence of concentration camps as early as 1933, as they served as a deterrent to resistance. The extermination camps, on the other hand, were kept strictly secret. To disguise the mass murder, even in internal correspondence, they only referred to it as "special treatment," "cleansing," "resettlement," or "evacuation." The SS referred to the extermination camps as concentration camps. Their internal organizational structures were also largely identical. The term "extermination camp" was only used later in historical scholarship and in court cases and serves to further categorize the camps.

Auschwitz (German: [ˈaʊ̯ʃvɪts]), also known as Oświęcim (Polish: [ɔˈɕfjɛɲ.t͡ɕim]), was a complex of over 40 concentration and extermination camps operated by Nazi Germany in occupied Poland (in a portion annexed into Germany in 1939) during World War II and the Holocaust. It consisted of Auschwitz I, the main camp (Stammlager) in Oświęcim; Auschwitz II-Birkenau, a concentration and extermination camp with gas chambers, Auschwitz III-Monowitz, a labour camp for the chemical conglomerate IG Farben, and dozens of subcamps. The camps became a major site of the Nazis' Final Solution to the Jewish question.

After Germany initiated World War II by invading Poland in September 1939, the Schutzstaffel (SS) converted Auschwitz I, an army barracks, into a prisoner-of-war camp. The initial transport of political detainees to Auschwitz consisted almost solely of Poles (for whom the camp was initially established). For the first two years, the majority of inmates were Polish. In May 1940, German criminals brought to the camp as functionaries established the camp's reputation for sadism. Prisoners were beaten, tortured, and executed for the most trivial of reasons. The first gassings—of Soviet and Polish prisoners—took place in block 11 of Auschwitz I around August 1941.

The Warsaw Ghetto Uprising was the 1943 act of Jewish resistance in the Warsaw Ghetto in German-occupied Poland during World War II to oppose Nazi Germany's final effort to transport the remaining ghetto population to the gas chambers of the Majdanek and Treblinka extermination camps.

After the Grossaktion Warsaw of summer 1942, in which more than a quarter of a million Jews were deported from the ghetto to Treblinka and murdered, the remaining Jews began to build bunkers and smuggle weapons and explosives into the ghetto. The left-wing Jewish Combat Organization (ŻOB) and right-wing Jewish Military Union (ŻZW) formed and began to train. A small resistance effort to another roundup in January 1943 was partially successful and spurred Polish resistance groups to support the Jews in earnest.

Holocaust denial is the negationist and antisemitic claim that Nazi Germany and its collaborators did not commit genocide against European Jews during World War II, ignoring overwhelming historical evidence to the contrary. Theories assert that the genocide of Jews is a fabrication or exaggeration. Holocaust denial includes making one or more of the following false claims: that Nazi Germany's "Final Solution" was aimed only at deporting Jews from the territory of the Third Reich and did not include their extermination; that Nazi authorities did not use extermination camps and gas chambers for the mass murder of Jews; that the actual number of Jews murdered is significantly lower than the accepted figure of approximately six million; and that the Holocaust is a hoax perpetrated by the Allies, Jews, or the Soviet Union.

Holocaust denial has roots in postwar Europe, beginning with writers such as Maurice Bardèche and Paul Rassinier. In the United States, the Institute for Historical Review gave Holocaust denial a pseudo-scholarly platform and helped spread it globally. In the Islamic world, Holocaust denial has been used to delegitimize Israel; deniers portray the Holocaust as a fabrication to justify the creation of a Jewish state. Iran is the leading state sponsor, embedding Holocaust denial into its official ideology through state-backed conferences and cartoon contests. In former Eastern Bloc countries, deniers do not deny the mass murder of Jews but deny the participation of their own nationals.