Nazi camps were among the most important sites of mass murder and genocide between 1939 and 1945. National Socialism, however, did not invent ‘concentration camps’. They were an institution already known during the second half of the nineteenth century that governments built before, during and after World War Two. Camps as a space of confinement for civilians who were not sentenced by the judiciary or interned as enemy aliens were both an addition to the existing prison system and a completely separate phenomenon. And camps installed under Nazi German hegemony could look quite different, from the use of empty industrial buildings to small areas of a single barracks or the standardised look of concentration camps, to large spaces confined by barbed wire and watchtowers with barracks and specific functional parts, like guards’ facilities or forced labour workshops. The latter shaped the general representation of camps both during the war and in post-war memory. And camps were different from another specific Nazi German institution, the ghetto for Jews, a space of isolation, starvation and confinement, and death before transporting the remaining population to killing centres.