Humanities › History & Culture Auschwitz Facts Share Flipboard Email Print Massimo Pizzotti/Getty Images History & Culture European History The Holocaust European History Figures & Events Wars & Battles European Revolutions Industry and Agriculture History in Europe American History African American History African History Ancient History and Culture Asian History Genealogy Inventions Latin American History Medieval & Renaissance History Military History The 20th Century Women's History View More By Jennifer Goss is a Holocaust historian and history educator. She serves as a consultant for the United States Holocaust Memorial Museum and the USC Shoah Foundation. our editorial process Jennifer L. Goss Updated January 23, 2020 Auschwitz, the largest and deadliest camp in the Nazi concentration and death camp system, was located in and around the small town of Oswiecim, Poland (37 miles west of Krakow). The complex consisted of three large camps and 45 smaller sub-camps. The Main Camp, also known as Auschwitz I, was established in April 1940 and was primarily used to house prisoners who were forced laborers. Auschwitz-Birkenau, also known as Auschwitz II, was located less than two miles away. It was established in October 1941 and was used as both a concentration and death camp. Buna-Monowitz, also known as Auschwitz III and “Buna,” was established in October 1942. Its purpose was to house laborers for neighboring industrial facilities. In total, it is estimated that 1.1 million of the 1.3 million individuals deported to Auschwitz were killed. The Soviet Army liberated the Auschwitz complex on January 27, 1945. Auschwitz I – Main Camp The initial environs where the camp was created had formerly been a Polish army barracks.The first prisoners were primarily Germans, transferred from the Sachsenhausen Camp (near Berlin) and Polish political prisoners transferred from Dachau and Tarnow.Auschwitz I had a single gas chamber and crematorium; however, it was not heavily utilized. After Auschwitz-Birkenau became operational, the facility was turned into a bomb shelter for Nazi officials who were located in offices in the vicinity.At its peak, Auschwitz I contained over 18,000 prisoners – mostly men.Prisoners in all of the Auschwitz camps were forced to wear striped attire and have their heads shaved. The latter was presumably for sanitation but also served the purpose of dehumanizing the victims. As the Eastern Front came closer, the striped uniforms often fell by the wayside and other attire was substituted.All of the Auschwitz camps implemented a tattoo system for prisoners who remained in the camp system. This differed from other camps which often required the number on the uniform only.Block 10 was known as the “Krankenbau” or hospital barrack. It had blacked out windows on the first floor to hide evidence of medical experiments that were being performed on prisoners within the building by doctors such as Josef Mengele and Carl Clauberg.Block 11 was the camp prison. The basement contained the first experimental gas chamber, which was tested on Soviet prisoners of war. Between Blocks 10 and 11, a closed courtyard contained an execution wall (the “Black Wall”), where prisoners were shot.The infamous “Arbeit Macht Frei” (“Work Shall Set You Free”) gate stands at the entrance of Auschwitz I.Camp Commandant Rudolf Hoess was hanged just outside Auschwitz I on April 16, 1947. Auschwitz II -- Auschwitz Birkenau Built in an open, swampy field less than two miles from Auschwitz I and across the main set of railroad tracks.Construction on the camp initially began in October 1941 with the initial intended purpose of being a camp for 125,000 prisoners of war.Birkenau had approximately 1.1 million people pass through its gates during its nearly three-year existence.When individuals arrived in Auschwitz-Birkenau, they were forced to undergo a Selektion, or sorting process, in which healthy adult persons who were desired for work were permitted to live while the remaining elderly, children and ill people were taken directly to the gas chambers.90% of all individuals who entered Birkenau perished – an estimated 1 million people total.9 out of every 10 people killed in Birkenau were Jewish.Over 50,000 Polish prisoners died in Birkenau and nearly 20,000 Gypsies.Separate camps were established within Birkenau for Jews from Theresienstadt and Gypsies. The former was established in the event of a Red Cross visit but was liquidated in July 1944 when it was evident that this visit would not occur.In May 1944, a train spur was built into the camp to aid with the processing of the Hungarian Jews. Prior to this point, victims were unloaded at a rail station between Auschwitz I and Auschwitz II.Birkenau contained four, large, gas chambers, each of which could kill up to 6,000 individuals per day. These gas chambers were attached to crematoriums that would burn the masses of dead bodies. The gas chambers were disguised as shower facilities to deceive the victims in order to keep them calm and cooperative throughout the process.The gas chambers utilized pruissic acid, trade name “Zyklon B.” This gas was commonly known as a pesticide in orchards and for prisoner clothing.A portion of the camp, “F Lager,” was a medical facility that was used for experiments as well as limited medical treatment of camp prisoners. It was staffed by Jewish prisoner-doctors and staff, as well as Nazi medical staff. The latter was primarily focused on experimentation.Prisoners in the camp often named sections of the camp themselves. For example, the warehousing portion of the camp was known as “Kanada.” An area slated for camp expansion that was swampy and mosquito-ridden was called “Mexico.”An uprising occurred in Birkenau in October 1944. Two of the crematoriums were destroyed during the uprising. It was staged largely by members of Sonderkommando in Crematoriums 2 and 4. (The Sonderkommando were groups of prisoners, mainly Jewish, who were forced to staff the gas chambers and crematoriums. They received better food and treatment in return, but the gruesome, heartbreaking work caused them to have a four-month turnover rate, on average, before meeting the same fate as the victims they processed.) Auschwitz III -- Buna-Monowitz Located several miles from the main complex, Auschwitz III bordered the town of Monowice, home of the Buna synthetic rubber works.The initial purpose for the camp’s establishment in October 1942 was to house laborers who were leased out to the rubber works. Much of its initial construction was funded by IG Farben, a company that benefited from this forced labor.Also contained a special Labor Education Department to reeducate non-Jewish prisoners who did not follow camp structure and policy.Monowitz, like Auschwitz I and Birkenau, was surrounded by electrified barbed wire.Elie Wiesel spent time in this camp after being processed through Birkenau with his father. The Auschwitz complex was the most notorious in the Nazi camp system. Today, it is a museum and educational center that hosts over 1 million visitors annually.