Ghettos, concentration camps and extermination camps.
The Allies (including Britain) stopped the Nazi concentration camps and the Holocaust by invading and defeating Nazi Germany.
Terrible
if you mean in the Soviet concentration camps, then poorly; they lost millions of soldiers in the camps.
The key distinction was between extermination camps and labour camps ("ordinary" concentration camps).
There werent American CIVILIANS killed in Nazi Concentration camps. Civillians implies that they were not serving. There were American men in the army who were killed in Nazi Concentration camps, but no civilians.
The extermination camps were top secret.
The camps were mainly in Germany and in Nazi-occupied Poland.
they were in Germany and through out Europe.
Recreation areas for A+ ;)
Concentration camps were built almost immediately after Hitler came to power. used as prisons and labour camps
In World War 1 (1914-18) there were no concentration camps. For the Nazi concentration camps, see the related question.