Muhammad Ali shocks the world when he defeats George Foreman in Zaire, winning back the heavyweight title, and becoming the most famous man on earth. He faces Joe Frazier in the brutal "Thrilla in Manila" and boxes for five more years before retiring in 1981. He is diagnosed with Parkinson's in 1984 but continues to travel the world spreading his Islamic faith and becomes a symbol of peace and hope.

Muhammad Ali battles his fiercest rival, Joe Frazier, and the U.S. government, as he attempts to regain the heavyweight title. He first loses to and then defeats Frazier, but to become champion again, he will have to beat George Foreman.

Cassius Clay publicly joins the Nation of Islam and takes the name Muhammad Ali. When he refuses induction into the Army, he is stripped of his title and forced into exile. After three years he returns to the ring, but he's lost a step.

Boxer Cassius Clay rises up the amateur ranks to win gold at the 1960 Olympics. He turns professional and moves to Miami, sharpening his boxing skills and honing his genius for self-promotion. Meanwhile, he quietly joins the Nation of Islam and becomes a confidant of Malcolm X. In 1964, he shocks the world by upsetting the heavily favored Sonny Liston to win the heavyweight championship.