Muhammad Ali (real name Cassius Clay) was a professional heavyweight boxer from 1960-1981, winning everything from the World Heavyweight Title to Olympic Gold. His most famous bouts were "The Rumble In The Jungle" vs George Foreman and "The Thrilla In Manilla" vs Chuck Wepner, the fight that inspired Rocky. He is regarded by many as one of the greatest boxers ever.
Ali was a strong believer in equality and did not believe in wars, claiming "War is against the teachings of the Holy Qur'an". If only more Muslims interpreted the Koran that way things could get much better. Anyway, he refused to serve in the Vietnam War, which led to him being stripped of his boxing belts and banned from boxing. During his enforced period out of the sport, he became much more than a sports star, but an activist for ending the war and inequality.