The Einsatzgruppen

They murdered more than a million people, sometimes in massive killing orgies that saw tens of thousands dead in only two days.

Consisting mostly of SS and police units, they were under the control of Heinrich Himmler and his deputies, Reinhard Heydrich and Ernst Kaltenbrunner.

They were the first Nazi units to commence the large-scale killing of Jews and other "undesirables"...