Browning describes the creation of the extermination camps, which were responsible for the largest number of deaths in the Final Solution, as bringing together three separate developments within the Third Reich: the concentration camps which had been established in Germany since 1933; an expansion of the gassing technology of the Nazi euthanasia programme to provide killing mechanism of greater efficiency and psychological detachment; and the creation of "factories of death" to be fed endless streams of victims by mass uprooting and deportation that utilized the experience and personnel from earlier population resettlement programmes—especially the HSSPF and Adolf Eichmann's RSHA for "Jewish affairs and evacuations".[115]
When did the Nazis decide to kill all the Jews of Europe? Was murder always in the mind of Adolf Hitler? These are some of the most difficult questions historians have to answer. Certainly, up until the invasion of the Soviet Union, Jews did manage to emigrate from Germany. Historians will never know precisely when the order for mass killing was given, but large-scale murders began with the invasion of Russia.
Title bestowed by Yad Vashem (the Israeli Holocaust remembrance authority) on certain gentiles who rescued Jews in opposition to Nazi efforts to annihilate them. The distinction is granted according to stringent criteria requiring conclusive evidence. Depending on the nature and extent of help, special kinds of recognition are bestowed upon Christians who saved Jews. To qualify for any one of the distinctions, Christian actions had to involve “extending help in saving a life; endangering one’s own life; absence of reward, monetary and otherwise; and similar considerations which make the rescuers’ deeds stand out above and beyond what can be termed ordinary help.” In part ambiguous, the criteria leave no doubt that those who saved Jews primarily because of payment do not fit the definition of righteous Christians.

On June 6, 1944, also known as D-Day, more than 150,000 Allied soldiers landed in France. In December the Germans started an unsuccessful counterattack in Belgium and northern France, known as the Battle of the Bulge. Continuing to gain momentum, the Soviets began an offensive in January 1945, liberating western Poland and then forcing Hungary to surrender.

Throughout the Middle Ages in Europe, Jews were subjected to antisemitism based on Christian theology, which blamed them for killing Jesus. Even after the Reformation, Catholicism and Lutheranism continued to persecute Jews, accusing them of blood libels and subjecting them to pogroms and expulsions.[60][61] The second half of the 19th century saw the emergence in the German empire and Austria-Hungary of the völkisch movement, which was developed by such thinkers as Houston Stewart Chamberlain and Paul de Lagarde. The movement embraced a pseudo-scientific racism that viewed Jews as a race whose members were locked in mortal combat with the Aryan race for world domination.[62] These ideas became commonplace throughout Germany,[63] with the professional classes adopting an ideology that did not see humans as racial equals with equal hereditary value.[64] Although the völkisch parties had support in elections at first, by 1914 they were no longer influential. This did not mean that antisemitism had disappeared; instead it was incorporated into the platforms of several mainstream political parties.[63]
Killing on a mass scale using gas chambers or gas vans was the main difference between the extermination and concentration camps.[269] From the end of 1941, the Germans built six extermination camps in occupied Poland: Auschwitz II-Birkenau, Majdanek, Chełmno, and the three Operation Reinhard camps at Belzec, Sobibor, and Treblinka II.[44][270] Maly Trostenets, a concentration camp in the Reichskommissariat Ostland, became a killing centre in 1942.[44] Gerlach writes that over three million Jews were murdered in 1942, the year that "marked the peak" of the mass murder of Jews.[271] At least 1.4 million of these were in the General Government area of Poland.[272]
The ideology of Nazism brought together elements of antisemitism, racial hygiene, and eugenics, and combined them with pan-Germanism and territorial expansionism with the goal of obtaining more Lebensraum (living space) for the Germanic people.[16] Nazi Germany attempted to obtain this new territory by attacking Poland and the Soviet Union, intending to deport or kill the Jews and Slavs living there, who were considered by the Nazis to be inferior to the Aryan master race.[17]