From to , Nazi Germany operated more than a thousand concentration camps German : Konzentrationslager [ a ] , including subcamps [ b ] on its own territory and in parts of German-occupied Europe. The first camps were established in March immediately after Adolf Hitler became Chancellor of Germany. Initially, most prisoners were members of the Communist Party of Germany , but as time went on different groups were arrested, including "habitual criminals", " asocials ", and Jews.
About 1. Following Allied military victories, the camps were gradually liberated in and , although hundreds of thousands of prisoners died in the death marches. Museums commemorating the victims of the Nazi regime have been established at many of the former camps and the Nazi concentration camp system has become a universal symbol of violence and terror. Concentration camps are conventionally held to have been invented by the British during the Second Boer War , but historian Dan Stone argues that there were precedents in other countries and that camps were "the logical extension of phenomena that had long characterized colonial rule".
The German Empire also established concentration camps during the Herero and Namaqua genocide β ; the death rate of these camps was 45 per cent, twice that of the British camps. During the First World War , eight to nine million prisoners of war were held in prisoner-of-war camps , some of them at locations which were later the sites of Nazi camps, such as Theresienstadt and Mauthausen.
Many prisoners held by Germany died as a result of intentional withholding of food and dangerous working conditions in violation of the Hague Convention. Hundreds of thousands were interned and subject to forced labor in harsh conditions.
On 30 January , Adolf Hitler became chancellor of Germany after striking a backroom deal with the previous chancellor, Franz von Papen. The Reichstag fire in February was the pretext for mass arrests. The Reichstag Fire Decree eliminated the right to personal freedom enshrined in the Weimar Constitution and provided a legal basis for detention without trial.
