Chelmno was the first extermination camp created by the Nazis in World War II. Located between Lodz and Poznan, Poland, Chelmno ("Kulemhof" in German) served as a strategic location for the early implementation of the Final Solution. It was a small town along the railway and was hidden within a wooded area. It was also close to the Lodz ghetto where the majority of Jews in the area lived.

Little is known about Chelmno, because the Nazis were careful to hide the atrocities they committed here. They burnt bodies and went to lengths to plant trees in the area to erase the entire crime.

Using the castle in Chelmno as headquarters, prisoners were brought here starting in December of 1941 thinking (as most at the start of the war) that they were being assigned to work camps. They were told to undress, hand over their valuables and prepare for "baths". Semi trucks were attached to the basement where people were loaded into the trailer. When the trailer was full, the door was shut, the ignition started and the exhaust pipe was attached, killing those inside with carbon monoxide. Then the trucks (three total), called "sonderwagons" by the Germans drove to a nearby wooded area where the dead were placed in mass graves.

It has been estimated that over a quarter million Jews were killed here along with many gypsies, Poles and Russian spies. The children of the town Lidice were also murdered here as retribution for the assassination of reichprotektor Reinhard Heidrich in Czechoslovakia.

The camp was used between December of 1941 thru April of 1943, then was shut down until 1944 when they built crematoriums and started to use Zyklon B gas instead of their sonderwagon methods. The Russians finally liberated the camp, but it had been completely destroyed and only two escaped survivors remained.