The Abyss | Seared Souls: S.C. Voices of the Holocaust
In 1939 and 1940, more than 70,000 Germans and Austrians, such as the chronically sick and the mentally retarded, had been gassed in six special euthanasia institutions. The euthanasia program became the training ground for the SS personnel, who would use these skills to manage the Nazi death camps.
Over 300 concentration camps now existed in Poland, in Germany and its outside territories. Jews were systematically rounded up for resettlement, they were told.