Birkenau (Auschwitz II) was by far the largest of the Auschwitz complex, located just a couple of kilometres from the main camp. Its initial purpose from 1941 was supposed to be to house 125k prisoners of war. But that never happened and it became a place to exterminate Jews. Those plans were made and the result was that mass extermination facilities were built and the gas chambers came into use in 1942.
Ten thousand Soviet POWs were brought from the Neuhammer am Quais POW camp to build the new facility. At first they were housed in the Auschwitz main camp. They were marched every day to the construction site in the village of Brzezinka to build Birkenau. BI, the first of the four planned Birkenau segments, was built in the village of Brzezinka in winter 1941/42. The construction segments were divided into sectors (“camps”) separated by electrified barbed-wire fences. Guard towers surrounded the entire camp. A three track railway spur and unloading ramp went into operation in May 1944.
The Germans built approximately 300 housing, administrative and infrastructure barracks and buildings at Birkenau, comprising 13 km of drainage ditches, 16 km of barbed wire fencing and more than 10 km of roads in the huge area of 140 hectares. The sheer scale of the site is vast.
Gas chambers, (known as bunkers 1 and 2), came on stream in 1942. The construction of four gigantic gas chambers and a crematoria began in mid 1942. According to German calculations, they estimated that 1.6 million people a year could be killed and burned there.
The Birkenau women’s camp opened in August 1942. Over 10 thousand women of various ethnic origins, but mostly Jewish, were transferred to Birkenau from Auschwitz I. Seven new administrative units were opened in 1943. They included the Gypsy Family Camp. Over 23 thousand Gypsies from Germany, Austria and surrounding territories were sent. The camp was liquidated in August 1944, when the approximately three thousand Gypsies still there were exterminated in the gas chambers.
Birkenau, like the whole Auschwitz complex, combined two functions in one place. Firstly as a concentration camp – a place where various categories of prisoners were imprisoned and slowly exterminated as a result of deliberately created inhumane conditions; and secondly as an extermination centre. Apart from the gas chambers and crematoria, the basic facilities of the extermination unit included the unloading ramp and the warehouses used for storing, sorting, and shipping the victims’ property.