Former German Nazi "Kulmhof am Ner" extermination camp

Chełmno or Kulmhof was the first of Nazi Germany's extermination camps and was situated 50 kilometres north of Łódź, near the village of Chełmno nad Nerem. Following the invasion of Poland in 1939, Germany annexed the area into the new territory of Reichsgau Wartheland. The camp, which was specifically intended for no other purpose than mass murder, operated from December 8, 1941 to April 11, 1943, parallel to Operation Reinhard during the deadliest phase of the Holocaust, and again from June 23, 1944 to January 18, 1945 during the Soviet counter-offensive.

Source: Wikipedia