The Warsaw concentration camp, or Gęsiówka, was a German concentration camp built on the ruins of the Warsaw Ghetto, around the Gęsiówka prison. This minor camp is absent from most standard accounts of the Holocaust. Over the course of its operation, some 8,000 to 9,000 prisoners were held there, performing slave labor. Some 4,000 to 5,000 of them died – in the death march out of the camp, in the Warsaw Uprising, and while in hiding following the uprising.