Dachau is widely regarded as the first concentration camp established by the Nazis. Opened on 22 March 1933, a mere 51 days after Hitler took power (and more than six years before the second World War even started). At first, this camp was used to suppress all (potential) political opposition and to "concentrate" political opponents into one prison so as "not to burden the regular prisons". Gradually Dachau (and other concentration camps) was to be used for anyone who would be called "enemy of the state". Even though conditions and forced labor were inhumane, Dachau was a concentration camp, not an extermination camp like Auschwitz.
Of Dachau's 206,206 prisoners from every possible demographic that were suspected to oppose the Nazi regime, 31,951 are believed to have died in the main camp and surrounding sub camps, most due to inhumane treatment, illness, disease and hardship. You can read more here.
By comparison, Auschwitz, much larger than Dachau, was one of 6 extermination camps, specifically designed to kill as many people as efficiently as possible. In Auschwitz II alone, more than 1,400,000 people were killed.
Nevertheless, for the Nazis, Dachau with its 124 sub camps became the organisational model for all concentration camps that were to follow.
One of the things that still strikes me about the Holocaust, is that I now realise that there were not just 23 (large) concentration camps (as I always thought there were), but that almost all of those main camps had a network of smaller camps around them (with from several thousand to sometimes less than a dozen prisoners).
Dachau is the second of a series of road trips that I'm undertaking to photograph the blue sky precisely above the location of every single one of the 1,075 concentration camps that have ever existed, as part of an installation/photography project called The Blue Skies Project.