They did not exist. They were built during the war.
world war 2
Concentration Camps Transit Camps Labour Camps Death Camps Extermination Camps.
concentration camps were places where Jews were kept in the 2nd world war and then the used to get killed there
Concentration Camps Were Widely Known For Exterminating Jewish Kind And Prisoners of War. Used in WWII By Nazis.
torturing jews
In World War 1 (1914-18) there were no concentration camps. For the Nazi concentration camps, see the related question.
The term Concentration camp was first used by the British in the Boer wars. this was very different form the concentration camps used in Nazi Germany. they were not death camps but camps in which the family of Boer rebels were imprisoned so that they could not aid the rebels. However concentration camps have been used before this (only they were not called concentration camps) they were used by the Spanish in the 1860's even American soldiers used similar camps on Cherokee and other native Americans in the 1830's so this type of military tactic has been around for a long time, but the term is British. Evidently, there are no real differences, but rather there are similarities between the English and the German concentration camps.
The Allies liberated many Nazi and Axis concentration camps in World War Two.The prisoners of war were sent to concentration camps.
prisoner of war camps for soldiers, concentration camps for civilians.
I think it was mainly the Germans who used the concentration camps to kill jewish people and to keep people hostage.
There wasn't cold war concentration camps unless you were a Russian and sent to Siberia.
Most concentration camps were liberated by the allied forces towards the end of the war.