Leon Gast’s now-classic documentary on the “Rumble in the Jungle”—Muhammad Ali’s triumphant Kinshasa fight against heavyweight champion George Foreman—took more than two decades to finish. By the time of completion, it had become a reflection on the responsibilities and demands of fame, a snapshot of a moment when black Americans were starting, partly thanks to Ali’s example, to embrace their African heritage en masse, and a hymn to Ali’s mesmerizing, canny presence outside the ring. With commentary by Spike Lee and Norman Mailer and appearances by B.B. King, The Seekers, and Brown—seen here greeting Ali at the airport, hanging out with Don King, and, in one scene, turning to the camera and making a passionate appeal for black empowerment.