Auschwitz concentration camp (German: Konzentrationslager Auschwitz, also KZ Auschwitz [kɔntsɛntʁaˈtsi̯oːnsˌlaːɡɐ ˈʔaʊʃvɪts] ( listen)) was a network of German Nazi concentration camps and extermination camps built and operated by the Third Reich in Polish areas annexed by Nazi Germany during World War II.