Oh and also there were no traces of zyclon B, a delousing agent used by the evil Nazis to save the jews from typhus, on any shower walls.

And I don't want to leave off my personal favorite - there's an actual giant chimney in Auschwitz, to this day right now, that's not connected to anything. Literally just a giant brick "chimney" that was constructed after the war by poor craftsmen, and it's still there, and it's definitely not part of the "official tour".