During World War II, Pilecki signed up to be jailed in Auschwitz, a German concentration camp, to tell the Allies about what is inside, and then escape. While inside the camp, he created a rebellion and told the Allies about the terrible things happening in Auschwitz as early as 1941. He escaped from the camp in 1943. He was a soldier in the Warsaw Uprising, which was an attack to free Warsaw from Nazi Germany. He was arrested in 1947 by Soviet secret police, and killed by them in 1948. Knowledge of the killing was kept secret until 1989, when Poland revealed his death. 