It's hard to believe it's taken 35 years for images this vibrant, this joyous, and this era-defining to reach the big screen. Yet that's the gestation period for Soul Power
, the concert film that finally brings to life the three-day music festival known as Zaire '74, which was intended to accompany the "Rumble in the Jungle" boxing match between Muhammad Ali and George Foreman (before a busted lip prompted Foreman to postpone by six weeks). The reason for the film's delay is clear, however -- its very existence was a direct response to how much footage wasn't considered germane to When We Were Kings
, Leon Gast's 1996 documentary about the fight, which i...