[12] From gaining power in January 1933 until the outbreak of war in September 1939, the Nazi persecution of the Jews in Germany was focused on intimidation, expropriating their money and property, and encouraging them to emigrate.

[15] Introduced at the end of 1937,[14] the "final solution of the Gypsy Question" entailed round-ups, expulsions, and incarceration of Romani in concentration camps built at, until this point, Dachau, Buchenwald, Flossenbürg, Mauthausen, Natzweiler, Ravensbruck, Taucha and Westerbork.

[18] The launch of Operation Barbarossa in June 1941 coincided with the German top echelon's newfound intent to pursue Hitler's new anti-Semitic plan to eradicate, rather than expel, Jews.

[19] Hitler's earlier ideas about forcible removal of Jews from the German-controlled territories to achieve Lebensraum were abandoned after the failure of the air campaign against Britain, initiating a naval blockade of Germany.

[20] On 31 July 1941, Reichsmarschall Hermann Göring wrote to Reinhard Heydrich (Himmler's deputy and chief of the RSHA),[21][22] authorising him to make the "necessary preparations" for a "total solution of the Jewish question" and coordinate with all affected organizations.

With the onset of Operation Barbarossa, mobile killing units of the SS, the Einsatzgruppen, and Order Police battalions were dispatched to the occupied Soviet Union for the express purpose of murdering all Jews.

This figure included not only Jews residing in Axis-controlled Europe, but also the Jewish populations of the United Kingdom and of neutral nations (Switzerland, Ireland, Sweden, Spain, Portugal, and European Turkey).

[2] Eichmann's biographer David Cesarani wrote that Heydrich's main purpose in convening the conference was to assert his authority over the various agencies dealing with Jewish issues.

"The simplest, most decisive way that Heydrich could ensure the smooth flow of deportations" to death camps, according to Cesarani, "was by asserting his total control over the fate of the Jews in the Reich and the east" under the single authority of the RSHA.

[33] The Nazi invasion of the Soviet Union codenamed Operation Barbarossa, which commenced on 22 June 1941, set in motion a "war of annihilation" which quickly opened the door to the systematic mass murder of European Jews.

[35] On 3 March 1941, Wehrmacht Joint Operations Staff Chief Alfred Jodl repeated Hitler's declaration that the "Jewish-Bolshevik intelligentsia would have to be eliminated" and that the forthcoming war would be a confrontation between two completely opposing cultures.

[45] A month later, the largest mass shooting of Soviet Jews took place on 29–30 September in the ravine of Babi Yar, near Kyiv, where more than 33,000 Jewish people of all ages were systematically machine-gunned.

[56] An Israeli historian Dina Porat claimed that the Final Solution, i.e.: "the systematic overall physical extermination of Jewish communities one after the other—began in Lithuania" during the massive German chase after the Red Army across the Reichskommissariat Ostland.

One of the first indiscriminate massacres of men, women, and children in Reichskommissariat Ukraine took the lives of over 4,000 Polish Jews in occupied Łuck on 2–4 July 1941, murdered by Einsatzkommando 4a assisted by the Ukrainian People's Militia.

[45][60] After an incident in Bila Tserkva in which 90 small children left behind had to be shot separately, Blobel requested that Jewish mothers hold them in their arms during mass shootings.

[64] In August 1942 in the presence of only a few German SS men over 5,000 Jews were massacred in Polish Zofjówka by the Ukrainian Auxiliary Police leading to the town's complete sweep from existence.

[84] Although other methods of extermination, such as the cyanic poison Zyklon B, were already being used at other Nazi killing centres such as Auschwitz, the Aktion Reinhard camps used lethal exhaust gases from captured tank engines.

[90] About two-thirds of the overall number of victims of the Final Solution were murdered before February 1943,[91] which included the main phase of the extermination programme in the West launched by Eichmann on 11 June 1942 from Berlin.

[92] The Holocaust trains run by the Deutsche Reichsbahn and several other national railway systems delivered condemned Jewish captives from as far as Belgium, Bulgaria, France, Greece, Hungary, Italy, Moravia, Netherlands, Romania, Slovakia, and even Scandinavia.

The difficult decision had to be made to have this people disappear from the earth.On 19 October 1943, five days after the prisoner revolt in Sobibór, Operation Reinhard was terminated by Odilo Globocnik on behalf of Himmler.

[98] The operation was followed by the single largest German massacre of Jews in the entire war carried out on 3 November 1943; with approximately 43,000 prisoners shot one-by-one simultaneously in three nearby locations by the Reserve Police Battalion 101 hand-in-hand with the Trawniki men from Ukraine.

[83] Unlike Belzec, Sobibor, Treblinka, and Lublin-Majdanek,[100] which were built in the occupied General Government territory inhabited by the largest concentrations of Jews,[101] the killing centre at Auschwitz subcamp of Birkenau operated in Polish areas annexed by Nazi Germany directly.

In the 1990s, the attention of mainstream historians moved away from the question of top executive orders triggering the Holocaust and focused on factors that were overlooked earlier, such as personal initiative and ingenuity of countless functionaries in charge of the killing fields.

[113] Hilberg divides this bureaucracy into four components or hierarchies: the Nazi Party, the civil service, industry, and the Wehrmacht armed forces—but their cooperation is viewed as "so complete that we may truly speak of their fusion into a machinery of destruction".

[116] With respect to the "functionalism versus intentionalism" debate about a master plan for the Final Solution, or the lack thereof, Hilberg posits what has been described as "a kind of structural determinism".

If a bureaucracy is motivated "to inflict maximum damage upon a group of people", it is "inevitable that a bureaucracy—no matter how decentralized its apparatus or how unplanned its activities—should push its victims through these stages", culminating in their annihilation.

During this time, the sites of the first extermination camps were selected, different methods of murder were tested, Jewish emigration was forbidden, and 11 transports departed for Łódź as a temporary holding station.

[119] Browning describes the creation of the extermination camps, which were responsible for the largest number of murders in the Final Solution, as bringing together three separate developments within Nazi Germany: the concentration camps which had been established in Germany since 1933; an expansion of the gassing technology of the Nazi euthanasia programme to provide a murder technique 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".

[122] David Cesarani emphasises the improvised, haphazard nature of Nazi policies in response to changing war time conditions in his overview, Final Solution: The Fate of the European Jews 1933–49 (2016).

"[132] When Himmler addressed senior SS personnel and leading members of the regime in the Posen speeches on 4 October 1943, he used "the fate of the Jews as a sort of blood bond to tie the civil and military leadership to the Nazi cause".