By 1974, Muhammad Ali was considered to be a faded boxing force, a shadow of the mercurial youngster who shocked the world a decade earlier. He was older, slower and had lost three of his best years because of a refusal to serve in the Vietnam War.
World champion George Foreman was at his peak, a fearsome fighting machine who had annihilated previously unbeaten Joe Frazier to win the title. He was, as his trainer called him, "a monster", considered invincible.
But when Foreman defended against Ali in Zaire, Ali defied the passage of time, taunting the champion with his famous "rope-a-dope" policy before winning in the eighth. By doing so, he became only the second man to regain the heavyweight title.
Extensive highlights of that momentous night in the heart of Africa celebrate his against-the-odds victory while friends and critics reveal how Ali surpassed even himself in his greatest triumph. Narrated by Michael Parkinson.