German Nazi concentration and extermination camp Majdanek

Majdanek was a Nazi concentration and extermination camp built and operated by the SS on the outskirts of the city of Lublin during the German occupation of Poland in World War II. It had seven gas chambers, two wooden gallows, and some 227 structures in all, placing it among the largest of Nazi concentration camps. Although initially intended for forced labor rather than extermination, it was used to murder people on an industrial scale during Operation Reinhard, the German plan to murder all Polish Jews within their own occupied homeland.

Source: Wikipedia