Nazi Germany operated many concentration camps during the 1930s and '40s, where millions of people were killed. Stalin also had many such installations in Russia at the time. In 2370, Quark told Benjamin Sisko that the Ferengi had nothing as barbaric as them. (DS9: "The Jem'Hadar") In the original script, Quark mentioned the Auschwitz concentration camp. In an alternate timeline, Vosk pitched the use of non-Aryan-targeting plagues as an alternative for extermination camps to a Nazi general. (ENT: "Storm Front")