Auschwitz-Birkenau (aka Auschwitz II) was the large extermination camp that was built three kilometres from the main camp, Auschwitz I. The camp was built on 175 hectares close to the former Polish village of Brzezinka (German: Birkenau). In March 1941, before construction began, the local population was evacuated and the houses demolished. Auschwitz-Birkenau was an extermination camp and a labour camp. Most of the prisoners arrived by railway in freight cars, often after being transported for days without food, water, or sanitary facilities. Many succumbed during the journey. Usually upon arrival at the platform (German: Rampe) outside of the camp, a selection took place to determine who would work and who would be gassed. Some transports were sent directly to the gas chambers without selecting people for labour. In 1943, the Germans were able to increase the 'production' in Auschwitz after four large crematoriums were built for burning the bodies. In 1944, the railway tracks were extended and the platform (Rampe) moved inside the camp, simplifying the mass murder of 440,000 Hungarian Jews. Auschwitz-Birkenau contained hundreds of barracks; the camp was encircled by deep ditches and a barbed wire electric fence. Part of the camp was designated for women and another part for Sinti and Roma (gypsies). Of the 23,000 Sinti and Roma that were transported to Auschwitz between February 1943 and June 1944, 21,000 were killed.