After the selection process was complete, those too ill or too young to walk to the crematoria were transported there on trucks or killed on the spot with a bullet to the head.[168][169] The belongings of the arrivals were seized by the SS and sorted in an area of the camp called "Canada", so called because Canada was seen as a land of plenty. Many of the SS at the camp enriched themselves by pilfering the confiscated property.[170]
At Auschwitz, after the chambers were filled, the doors were shut and pellets of Zyklon-B were dropped into the chambers through vents,[293] releasing toxic prussic acid, or hydrogen cyanide.[294] Those inside died within 20 minutes; the speed of death depended on how close the inmate was standing to a gas vent, according to the commandant Rudolf Höss, who estimated that about one-third of the victims died immediately.[295] Johann Kremer, an SS doctor who oversaw the gassings, testified that: "Shouting and screaming of the victims could be heard through the opening and it was clear that they fought for their lives."[296] The gas was then pumped out, the bodies were removed, gold fillings in their teeth were extracted, and women's hair was cut.[297] The work was done by the Sonderkommando, work groups of mostly Jewish prisoners.[298] At Auschwitz, the bodies were at first buried in deep pits and covered with lime, but between September and November 1942, on the orders of Himmler, they were dug up and burned. In early 1943, new gas chambers and crematoria were built to accommodate the numbers.[299]
Treatment inside the concentration camps were horrible. Prisoners were given tiny rations of food and forced into physical labor. They often slept more than three to a bed without pillows or blankets, even in the winter months. In many concentration camps, Nazi doctors conducted medical experiments on prisoners against their will, in many cases killing the prisoners in the process.
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.[8] Immediately after the Nazi seizure of power in Germany, boycotts of German Jews and acts of violence against them became ubiquitous,[9] and legislation was passed excluding them from the civil service and certain professions, including the law.[10][a] Harassment and economic pressure were used to encourage them to leave Germany; their businesses were denied access to markets, forbidden to advertise in newspapers, and deprived of government contracts.[11]

In 1916, General Alexei Brusilov had used surprise and infiltration tactics during the Brusilov Offensive. Later, Marshal Mikhail Tukhachevsky, Georgii Isserson and other members of the Red Army developed a concept of deep battle from the experience of the Polish–Soviet War. These concepts would guide Red Army doctrine throughout World War II. Realising the limitations of infantry and cavalry, Tukhachevsky was an advocate of mechanised formations and the large-scale industrialisation required. Robert Watt (2008) wrote that blitzkrieg holds little in common with Soviet deep battle.[48] In 2002, H. P. Willmott had noted that deep battle contained two important differences: it was a doctrine of total war, not limited operations, and decisive battle was rejected in favour of several large, simultaneous offensives.[49]
In chambers II and III, the killings took place in underground rooms, and the corpses were carried to the five ovens by an electrically operated lift. Before cremation gold teeth and any other valuables, such as rings, were removed from the corpses. In IV and V the gas chambers and ovens were on the same level, but the ovens were so poorly built and the usage was so great that they repeatedly malfunctioned and had to be abandoned. The corpses were finally burned outside, in the open, as in 1943. Jewish Sonderkommandos worked the crematoria under SS supervision.
Entrance is free, without a ticket, though donations are encouraged. Because of the large numbers of visitors entry to the Auschwitz-I site is exclusively on a guided group basis during the middle part of the day - as of 2019, between 10am and 12pm during December, between 10am and 1pm in November, January, February and March, between 10am and 4pm in April, May, September and October, and between 9am and 5pm in June, July and August.
After Germany’s loss in WWI, the Treaty of Versailles punished Germany by placing tough restrictions on the country. The treaty made Germany take full responsibility for the war, reduced the extent of German territory, severely limited the size and placement of their armed forces, and forced Germany to pay the allied powers reparations. These restrictions not only increased social unrest but, combined with the start of the Great Depression, collapsed the German economy as inflation rose alongside unemployment.

With this police infrastructure in place, opponents of the Nazis were terrorized, beaten, or sent to one of the concentration camps the Germans built to incarcerate them. Dachau, just outside of Munich, was the first such camp built for political prisoners. Dachau's purpose changed over time and eventually became another brutal concentration camp for Jews.

Irena Adamowicz Gino Bartali Archbishop Damaskinos Odoardo Focherini Francis Foley Helen of Greece and Denmark Princess Alice of Battenberg Marianne Golz Jane Haining Feng-Shan Ho Wilm Hosenfeld Constantin Karadja Jan Karski Valdemar Langlet Carl Lutz Aristides de Sousa Mendes Tadeusz Pankiewicz Giorgio Perlasca Marion Pritchard Ángel Sanz Briz Oskar Schindler Anton Schmid Irena Sendler Klymentiy Sheptytsky Ona Šimaitė Henryk Sławik Tina Strobos Chiune Sugihara Casper ten Boom Corrie ten Boom Johan van Hulst Raimondo Viale Raoul Wallenberg Johan Hendrik Weidner Rudolf Weigl Jan Zwartendijk