Auschwitz II (also known as Birkenau) was the biggest.
Auschwitz Birkenau, it acts as an death camp but it's an extermination camp.
Treblinka extermination camp
Belzec extermination camp was created in 1942.
Belzec extermination camp ended in 1942.
Treblinka extermination camp was created in 1942.
Treblinka extermination camp ended in 1943.
Chełmno extermination camp ended in 1943.
Chełmno extermination camp was created in 1941.
Sobibor extermination camp was created in 1943.
1. was the original camp 2. was the extermination centre and largest camp 3. was for the Buna workers
Auschwitz I was the original Auschwitz camp, set up in May 1940, mainly for Polish political prisoners and the Polish elites. It also housed the main administrative offices for the whole complex of camps as well as the blocks where medical experiments were carried out, and execution chambers.
Belzec was an extermination camp.