The early career of Cassius Clay includes a gold medal win at the 1960 Olympics in Rome; turning pro, he becomes heavyweight champion at age 22. Changing his name after converting to Islam, Muhammad Ali is stripped of his title for refusing induction into the military.

The first three-time heavyweight champion of the world, but the toll of so many historic ring encounters starts to show. "The Greatest" travels the globe as a goodwill ambassador, philanthropist & activist and is defined as much by his humanity as his feats in the ring.