The Maly Trostenets, or Maly Trascianiec, concentration camp sits on the outskirts of Minsk, Belarus, originally built by the Nazis in the summer of 1941, on the site of a Soviet kolkhoz (a collective farm).
The camp initially held Soviet prisoners of war that were captured after the German advance on the Soviet Union, which began on June 22, 1941, known as Operation Barbarossa. But it became a Vernichtungslager, or an extermination camp, on May 10, 1942, when the first transport of Jews arrived there, from Germany, Poland, the Netherlands, Austria, and the Protectorate of Bohemia and Moravia (present-day Czech Republic).
Many were even killed before reaching the camp, as they were brought to the nearby Blagovshchina (Благовщина) and Shashkovka (Шашковка) Forests, where they were shot in the back of the neck. Most of the victims were lined up in front of large pits and shot. Tractors then flattened the pits out. The prisoners in the camp were forced to sort through the victims’ possessions and maintain the camp. However, the primary purpose of the extermination camp was the eradication of the Jewish population of Minsk and the surrounding areas, by means of mobile gas chambers.
In 1943, the Germans began mass extermination of the prisoners in the camp. For more, see http://www.jewishvirtuallibrary.org/jsource/Holocaust/malytrostenets.html.