Chełmno was established in 1941 as one of the killing centres of Operation Reinhard in German-occupied Poland. Victims were deceived into entering the back of vans, which were wired so that the exhaust fumes gassed those inside. The bodies were then buried in the nearby forest. At least 172,000 people were killed at Chełmno between December 1941 and March 1943, and between June and July 1944 when it was briefly re-opened.
