In the late 1930's the
Nazis
killed thousands of handicapped Germans by lethal injection and
poisonous gas. After the German invasion of the Soviet Union in
June 1941, mobile killing units following in the wake of the
German Army began shooting massive numbers of Jews and Gypsies in
open fields and ravines on the outskirts of conquered cities and
towns.
Eventually the Nazis created a more secluded and organized method
of killing. Extermination
centers were established in occupied Poland with
special apparatus especially designed for mass murder. Giant death
machines.
Victims were deported to these centers from Western Europe and
from the ghettos in Eastern Europe which the Nazis had
established. In addition, millions died in the ghettos as a result
of forced labor, starvation, exposure, brutality, disease, and
execution.
The Mauthausen Concentration Camp (known from the summer of 1940 as Mauthausen-Gusen Concentration Camp) grew to become a large group of Nazi concentration camps that were built around the villages of Mauthausen and Gusen in Upper Austria.
Initially a single camp at Mauthausen, it expanded over time to become one of the largest labour camp complexes in German-controlled Europe.
The exact death toll of the Mauthausen-Gusen complex is impossible
to calculate. Various historians place it at between 120,000 and
320,000 (Material licensed under the GNU
Free Documentation License from Wikipedia).