National Geographic's Heart of Africa (PBS, 8-9 p.m.): This well-done series exploring Africa's Great Rift Valley features spectacular photography, exotic animals, and overblown narration. Emmy-winning filmmaker Alan Root travels to Virunga National Park in Zaire. He journeys from the glaciers of Mountains of the Moon - the fabled source of the Nile - to the volcanoes that ridge the tropical lowlands. Civet cats, hippos, and monitor lizards abound.
The best moment of the series belongs to Virunga's most-famous inhabitants: the mountain gorillas. In a sweetly ironic sequence, a group of gorillas are captivated by a lizard moseying through their midst. Perhaps, narrator Avery Brooks says, humans aren't the only naturalists in Virunga.
Tuesday's segment dives under Lake Tanganyika to plumb its gorgeous, well-stocked depths; and the final part, on Wednesday, journeys to Congo's primeval forest.
A Prelude to the Games (NBC, 9-11 p.m.): Bob Costas hosts this collage of Olympic-related stories by a world-class mix of writers and documentarians. The makers of "Hoop Dreams" team up with Sports Illustrated's Alexander Wolff to report on the former Yugoslavian basketball team, which has been torn apart by war. Other highlights: profiles of US gymnast Dominique Moceanu, the youngest woman to win the US national championship; and Cuban runner Ana Quirot.
All-Star Countryfest '96 (CBS, 9-11 p.m.): Alabama, Pam Tillis, the Charlie Daniels Band, and Patty Loveless rev up for a hoedown at Atlanta's Motor Speedway for 250,000 of their closest fans.
CBS Reports (CBS, 9-10 p.m.): Fidel Castro takes Dan Rather on a tour down memory lane in this unusually reflective interview. The two journey to the Sierra Maestras, where the fight of the "last revolutionary" began 37 years ago. US officials and Castro's brother and sister provide criticism and insight into this complex figure.
*Please check local listings for these programs.