Witold Pilecki (1901–1948) was a Polish cavalry officer and resistance fighter. The Holocaust Memorial Day Trust identifies him as the only known voluntary inmate of Auschwitz, where he spent more than two years gathering intelligence, organizing resistance, escaping in 1943, and writing reports before his later execution after torture and a sham trial. The Auschwitz-Birkenau Memorial and Museum confirms his voluntary September 1940 infiltration mission, his underground communication and resistance work, his April 1943 escape, and his later execution by communist authorities. The Institute of National Remembrance confirms that Pilecki was executed at Mokotów Prison on 25 May 1948 and later posthumously honored. His worth is not only that he survived Auschwitz. It is that he entered a death machine to make evidence, then left behind a report that outlived both the Nazis who built the camp and the regime that tried to bury him.