Auschwitz-Birkenau became the killing centre where the largest numbers of European Jews were killed. By mid 1942, mass gassing of Jews using Zyklon-B began at Auschwitz , where extermination was conducted on an industrial scale with some estimates running as high as three million persons eventually killed through gassing, starvation, disease, shooting, and burning ...


Sources:
A Teachers Guide to the Holocaust
Museum Auschwitz: KL-Auschwitz
Simon Wiesenthal Center