In October 1941, work began on Auschwitz II, or Birkenau, located outside the nearby village of Brzezinka. There the SS later developed a huge concentration camp and extermination complex that included some 300 prison barracks; four large so-called Badeanstalten (German: “bathhouses”), in which prisoners were gassed to death; Leichenkeller (“corpse cellars”), in which their bodies were stored; and Einäscherungsöfen (“cremating ovens”). Another camp (Buna-Monowitz), near the village of Dwory, later called Auschwitz III, became in May 1942 a slave-labour camp supplying workers for the nearby chemical and synthetic-rubber works of IG Farben. In addition, Auschwitz became the nexus of a complex of 45 smaller subcamps in the region, most of which housed slave labourers. During most of the period from 1940 to 1945, the commandant of the central Auschwitz camps was SS-Hauptsturmführer (Capt.) and ultimately SS-Obersturmbannführer (Lieut. Col.) Rudolf Franz Hoess (Höss).
The party grew out of smaller political groups with a nationalist orientation that formed in the last years of World War I. In 1918, a league called the Freier Arbeiterausschuss für einen guten Frieden (Free Workers' Committee for a good Peace) was created in Bremen, Germany. On 7 March 1918, Anton Drexler, an avid German nationalist, formed a branch of this league in Munich. Drexler was a local locksmith who had been a member of the militarist Fatherland Party during World War I and was bitterly opposed to the armistice of November 1918 and the revolutionary upheavals that followed. Drexler followed the views of militant nationalists of the day, such as opposing the Treaty of Versailles, having antisemitic, anti-monarchist and anti-Marxist views, as well as believing in the superiority of Germans whom they claimed to be part of the Aryan "master race" (Herrenvolk). However, he also accused international capitalism of being a Jewish-dominated movement and denounced capitalists for war profiteering in World War I. Drexler saw the political violence and instability in Germany as the result of the Weimar Republic being out-of-touch with the masses, especially the lower classes. Drexler emphasised the need for a synthesis of völkisch nationalism with a form of economic socialism, in order to create a popular nationalist-oriented workers' movement that could challenge the rise of Communism and internationalist politics. These were all well-known themes popular with various Weimar paramilitary groups such as the Freikorps.
Use of the word "concentration" came from the idea of confining people in one place because they belong to a group that is considered undesirable in some way. The term itself originated in 1897 when the "reconcentration camps" were set up in Cuba by General Valeriano Weyler. In the past, the U.S. government had used concentration camps against Native Americans and the British had also used them during the Second Boer War. Between 1904 and 1908, the Schutztruppe of the Imperial German Army operated concentration camps in German South-West Africa (now Namibia) as part of its genocide of the Herero and Namaqua peoples. The Shark Island Concentration Camp in Lüderitz was the largest camp and the one with the harshest conditions.