This article is from the Holocaust FAQ, by Ken McVay email@example.com with numerous contributions by others.
Indeed, a water reservoir in Auschwitz I (the main camp) was
converted to a swimming pool which was used by the camp's staff.
Other means of entertainment for the SS personnel existed - a band
composed of prisoners, and a brothel. How this "proves" that
Auschwitz was not an extermination center is beyond the author of