Lublin, Poland: Majdenek, located on the outskirts of Lublin, Poland, was one of the largest concentration and extermination camps after Auschwitz. In operation from 1941-1944, roughly 200,000 people were killed in the camp, with an estimated half of those being Polish Jews. Majedenk was one of the only camps where Zyclon B was used to poison people en masse. A museum was opened immediately after the camps closure, and it maintains a large number of exhibits, most of which are composed of items confiscated from prisoners. A large pile of shoes on loan from Majendek is on display at the United States Memorial Holocaust Museum. The camp grounds have been maintained and a number of buildings remain today, including several guard towers, barracks and crematoriums. The ashes of the victims rest inside of a special mausoleum on the camp grounds.