Rudolf Hess (1894-1987) was a German National Socialist who was Adolf Hitler's deputy as party leader. He created an international sensation when in 1941 he secretly flew to Great Britain on an abortive self-styled mission to negotiate a peace between Britain and Germany. Hess joined the fledgling Nazi Party in 1920 and quickly became Hitler's friend and confidant. After WWII, he was tried at the Nürnberg war crimes trials, convicted, and given a life sentence. He served his sentence at Spandau prison in Berlin, where from 1966 he was the sole inmate.
—Britannica