He was the most feared man in boxing—a glowering, unstoppable force with a criminal past and ties to the mob. But Sonny Liston’s reign as heavyweight champion was as brief as it was controversial. This episode of Biography explores the life of the man who rose from a prison boxing program to the pinnacle of the sport, only to be dethroned by a young Cassius Clay. From the 'phantom punch' to his mysterious and lonely death in Las Vegas, we look behind the scowl of the champion that America refused to love.