The notorious World War II death camp was liberated by the Red Army on 27 January 1945 - which was later designated as International Holocaust Remembrance Day. When Soviet troops entered the camp, they found only 7,500 prisoners alive - while the number of those exterminated there is estimated at over one million.
Horrifying photos from the camp became one of the most shocking revelations of Nazi crimes in Europe and have become a constant reminder of the atrocities of war.