After the Wannsee Conference of 1942, the Germans established death camps at Belzec, Sobibor and Treblinka. Their sole purpose was murder. They were set up near railway lines to make transportation of the victims easy. As they were purely killing centres, there were no selections. The victims were sent directly to the gas chambers.
A concentration camp to house Soviet prisoners of war and Poles had been established at Majdanek, close to the Polish city of Lublin, during 1941. In the spring of 1942 gas chambers and crematoria were added, turning Majdanek into an extermination camp that would murder 78,000 people.
Auschwitz-Birkenau, the most infamous of the Nazi death camps, was a massive concentration, forced labour and extermination camp at the centre of a network of more than 40 satellite camps. Upwards of 80 per cent of those Jews transported to Auschwitz-Birkenau were selected for immediate death.