A concentration camp is a facility where large numbers of people are detained, often without trial. These camps are typically used during times of war or political unrest to imprison individuals considered a threat to the state or society. Conditions in concentration camps are usually harsh, with limited access to food, medical care, and basic human rights. Historically, concentration camps have been associated with various regimes, most notably the Nazi regime during World War II, which imprisoned millions, including Jews, political dissidents, and other targeted groups. The term can also apply to other instances of mass detention throughout history.