"Fire brigade reservoir built in the form of a swimming pool, probably in early 1944"
In 1947 a Jewish Auschwitz survivor, stated Auschwitz had a swimming pool:
"The working hours were modified on Sundays and holidays,
"He was gone, leaving Winston holding the scrap of paper, which this time there was no need to conceal. Nevertheless he carefully memorized what was written on it, and some hours later dropped it into the memory hole along with a mass of other papers." - 1984 by George Orwell, chapter 14