Their was only about 20 Major concentration camps.
The main types of Concentration Camps were Concentration Camps and Extermination Camps.
No conflict caused concentration camps during WWII. Nazi Concentration Camps pre-dated WWII, though when Germany too over more territories they built more camps.
during World War 2 in Germany
The 4 major Concentration Camps during the Holocaust were:AuschwitzTreblinkaBelzecSobibor
Auschwitz wasn't that different from other camps. It was just the largest one out of all the concentration camps.
In World War 1 (1914-18) there were no concentration camps. For the Nazi concentration camps, see the related question.
In concentration camps