The Killing fields of Nazi Germany
The Concentration camps started out in January 1933 after Hitler's rise to power. Then Hitler wanted to centralize the concentration camps in Germany into a system. So the camps had certain staff members who did their job and had normal routines for the prisoners. They made the prisoners do forced labor to accomplish goals such as getting coal, but otherwise they were "annihilated through work". And the camps started to expand, and by 1939 there were 6 camps at work in Germany.
What was the Holocaust?
The Holocaust was the state sponsored, systematic persecution and annihalation of European Jewry by Nazi Germany and its collaborators between 1933 and 1945.