WEEKEND TV : Cable Eyes National Geographic, Terrorism

Cable programs on the wonders of nature, terrorism and the reigning queen of pop highlight this weekend’s small-screen lineup.

Sunday at 6 p.m., TBS offers “National Geographic Explorer: Greatest Moments,” a two-hour retrospective of the show’s best segments during the last five years. Among those segments are reports on Arctic wolf packs, shark-proof underwater suits, the millions of red crabs that swarm Christmas Island and a mountain climber with artificial limbs.

The Discovery Channel begins a six-part documentary series, “Terrorism: A World in Shadows,” Sunday at 7 p.m. (with a repeat at 10 p.m.). The series examines the who, what and whys of terrorism and its threat to world order and stability.

If you didn’t get enough of Madonna when she dogged Arsenio Hall on his talk show earlier this week, MTV has an entire weekend of specials on the pop siren, today from noon to 4 p.m. and again at 8 p.m., and Sunday at 2:30 p.m. These specials include live reports from the openning of Madonna’s U.S. concert tour in Houston.

And if you don’t have cable, KCET Channel 28 screens contrasting views of World War I tonight beginning at 10 p.m. with Stanley Kubrick’s anti-war classic “Paths of Glory.” Gary Cooper and Helen Hayes follow at 11:30 p.m. in the romantic movie-version of Ernest Hemingway’s “A Farewell to Arms.”