Poison gas used in Nazi extermination camps. A cyanide compound originally developed for fumigation purposes in the 1920s, Zyklon-B was actually a crystalline compound which gave off hydrogen cyanide gas when exposed to the air.
It was first used against humans in a euthanasia program 1939, aimed at ridding Germany of lunatics, incurable invalids, and other “undesirables”. The victims were induced to enter a “shower bath”, Zyklon-B was released, and the gas killed them in a few minutes. When the extermination camps were set up, this method was adopted as standard and was responsible for several million deaths. The inventor, Dr. Bruno Tesch, was convicted of war crimes and executed for his manufacture and supply of the substance to the camps.