The term "Final Solution" was a euphemism used by the Nazis to refer to their plan for the annihilation of the Jewish people. Historians have shown that the usual tendency of the German leadership was to be extremely guarded when discussing the Final Solution. Euphemisms were, in Mark Roseman's words, "their normal mode of communicating about murder".
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. According to the Nazi Party policy statement, the Jews and Gypsies (although numerically fewer), were the only "alien people in Europe". In 1936, the Bureau of Romani Affairs in Munich was taken over by Interpol and renamed The Center for Combating the Gypsy Menace. Introduced at the end of 1937, the "final solution of the Gypsy Question" entailed round-ups, expulsions, and incarceration of Romani in concentration camps built at, until this point in time, Dachau, Buchenwald, Flossenbürg, Mauthausen, Natzweiler, Ravensbruck, Taucha, and Westerbork. After the Anschluss with Austria in 1938, special offices were established in Vienna and Berlin to "facilitate" Jewish emigration, without covert plans for their forthcoming annihilation.
The outbreak of war and the invasion of Poland brought a population of 3.5 million Polish Jews under the control of the Nazi and Soviet security forces, and marked the start of a far more savage persecution, including mass killings. In the German-occupied zone of Poland, Jews were forced into hundreds of makeshift ghettos, pending other arrangements. Two years later, with the launch of Operation Barbarossa, the invasion of the Soviet Union in June 1941, the German top echelon began to pursue Hitler's new anti-Semitic plan to eradicate, rather than expel, Jews. Hitler's earlier ideas about forcible removal of Jews from the German-controlled territories in order to achieve Lebensraum were abandoned after the failure of the air campaign against Britain, initiating a naval blockade of Germany. Reichsführer-SS Heinrich Himmler became the chief architect of a new plan, which came to be called The Final Solution to the Jewish Question. On 31 July 1941, Reichsmarschall Hermann Göring wrote to Reinhard Heydrich (Himmler's deputy and chief of the RSHA), instructing Heydrich to submit concrete proposals for the implementation of the new projected goal.
Broadly speaking, the extermination of Jews was carried out in two major operations. 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 killing all Jews. During the early stages of the invasion, Himmler himself visited Białystok in the beginning of July 1941, and requested that, "as a matter of principle, any Jew" behind the German-Soviet frontier was to be "regarded as a partisan". His new orders gave the SS and police leaders full authority for the mass murder behind the front lines. By August 1941, all Jewish men, women, and children were shot. In the second phase of annihilation, the Jewish inhabitants of central, western, and south-eastern Europe were transported by Holocaust trains to camps with newly-built gassing facilities. Raul Hilberg wrote: "In essence, the killers of the occupied USSR moved to the victims, whereas outside this arena, the victims were brought to the killers. The two operations constitute an evolution not only chronologically, but also in complexity." Massacres of about one million Jews occurred before plans for the Final Solution were fully implemented in 1942, but it was only with the decision to annihilate the entire Jewish population that extermination camps such as Auschwitz II Birkenau and Treblinka were fitted with permanent gas chambers to kill large numbers of Jews in a relatively short period of time.
The villa at 56–58 Am Großen Wannsee, where the Wannsee Conference
was held, is now a memorial and museum.
The plans to exterminate all the Jews of Europe was formalized at the Wannsee Conference, held at an SS guesthouse near Berlin, on 20 January 1942. The conference was chaired by Heydrich and attended by 15 senior officials of the Nazi Party and the German government. Most of those attending were representatives of the Interior Ministry, the Foreign Ministry, and the Justice Ministry, including Ministers for the Eastern Territories. At the conference, Heydrich indicated that approximately 11,000,000 Jews in Europe would fall under the provisions of the "Final Solution". 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). 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. A copy of the minutes of this meeting was found by the Allies in March 1947; it was too late to serve as evidence during the first Nuremberg Trial, but was used by prosecutor General Telford Taylor in the subsequent Nuremberg Trials.
After the end of World War II, surviving archival documents provided a clear record of the Final Solution policies and actions of Nazi Germany. They included the Wannsee Conference Protocol, which documented the co-operation of various German state agencies in the SS-led Holocaust, as well as some 3,000 tons of original German records captured by Allied armies, including the Einsatzgruppen reports, which documented the progress of the mobile killing units assigned, among other tasks, to kill Jewish civilians during the attack on the Soviet Union in 1941. The evidential proof which documented the mechanism of the Holocaust was submitted at Nuremberg.