Survivor Samuel Willenberg recounts Treblinka uprising
2 August 2011 Last updated at 06:21 BST
It is 68 years since more than a one thousand Jewish prisoners at the Nazi death camp, Treblinka, rose up against their guards and attempted to escape.
Treblinka was one of the most notorious extermination camps in occupied Poland.
Between 1942 and 1943 around 870,000 Jews were killed there, according to Israel's Holocaust Memorial, Yad Vashem.
Survivor Samuel Willenberg, 87, has told the BBC's Bethany Bell about the horrors he saw, and their effect on his life.