January 27 will mark the 70th anniversary of the liberation of Auschwitz where at least 1.1 million people, mostly Jews, were murdered by the Nazis.

Set up in 1940 by occupying Nazi forces near the town of Oswiecim in what is now southern Poland, Auschwitz became the centrepiece in Adolf Hitler's "final solution" plan to exterminate the Jews.

Men, women and children, mostly Jewish, but also Gypsies, Russians, Poles and gays from all over Nazi-occupied Europe were transported to Auschwitz in overcrowded cattle trains. When they arrived at the camp, they faced a selection process. SS doctors decided which prisoners were suitable for labour and which should be killed immediately. The elderly and women with children were killed in the camp's gas chambers using the pesticide Zyklon B .

Those who survived the selection process were stripped of their clothes, belongings and identity, and had a number tattooed on their arm. They were issued with striped uniforms and marched to rows of accommodation blocks to begin their lives in the camp.

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An aerial photo of Auschwitz I taken on 25 August 1944 shows a line of new arrivals being registered. It also shows the location of a gas chamber, crematorium and execution wallUS National Archives
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An aerial photo of Birkenau Extermination Camp, taken on 13 September 1944, shows the railway lines, rows of accommodation huts and several gas chambersUS National Archives
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In this aerial photo of Auschwitz-Birkenau taken by a South African Air force plane on 25 August, 1944, the selection process of a recently arrived group has been completed, and those selected to die are being to taken to Crematorium II. Also visible is a cultivated garden in the courtyard of Crematorium II, the open gate into it, and Crematorium III. The basement undressing rooms and gas chambers of both complexes can also be seen. This annotated image was released by the Central Intelligence Agency in 1979South African Air Force
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Jewish women and children are pictured getting off the train upon their arrival at Auschwitz extermination campAFP
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May 1944: Jewish men and boys, with yellow stars sewn on their coats, arrive at Auschwitz concentration campHulton Archive/Getty Images
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1940: Deportees emerge from the overcrowded cattle trains before being sorted by SS doctors in a selection processKeystone/Getty Images
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Beds, on which four or five people had to sleep, in Auschwitz concentration campThree Lions/Getty Images
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View of a open door on one of the ovens at Auschwitz. The ovens were primarily used to incinerate the corpses of those inmates who were executed in gas chambersGabriel Hackett/Getty Images
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A picture taken in April 1945 at Dachau concentration camp shows a young man checking the numbers tattooed on the arms of Jewish prisoners coming from AuschwitzAFP
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When the camp was liberated, Soviet soldiers found a huge pile of prosthetic limbs belonging to victims murdered in the gas chambersAFP
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Prisoners who survived the Auschwitz death camp are seen in their barracks shortly after the camp was liberatedReuters
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Children stand behind a barbed wire fence at the Nazi concentration camp at Auschwitz as it is liberated by the Red ArmyKeystone/Getty Images
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Children who survived Auschwitz show their tattooed identification numbersReuters
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Soviet soldiers interview some of the prisoners they liberated in January 1945Reuters
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Some of the prisoners who survived the Nazi Auschwitz death camp are liberatedReuters
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The body of a female prisoner is seen lying in the snow when Auschwitz was liberated by the Russians in January 1945Reuters
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A pile of human bones and skulls is seen in 1944 at the Majdanek camp on the outskirts of Lublin, the second largest death camp in German-occupied Poland after Auschwitz, following its liberation in 1944 by Russian troopsAFP
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Bodies of prisoners are seen lying in the Nazi Auschwitz death camp shortly after it was liberatedReuters

Auschwitz was liberated by the Soviet Red Army on 27 January 1945. About 200,000 inmates survived.