“Explorer” (8 p.m., National Geographic) correspondent Lisa Ling goes “Inside North Korea” for a hidden-camera glance at the world’s most secretive dictatorship. Known as the “hermit kingdom,” North Korea has done a remarkable and creepy job of keeping the rest of the world at bay. A land where cell phones and the Internet are forbidden, Korea boasts one of the world’s largest armies and a border bristling with land mines and barbed-wire fences. And these are not to prevent an invasion from South Korea but to keep its starving population from defecting.

Ling joined Dr. Sanduk Ruit, an eye surgeon from Nepal who had volunteered to perform more than 1,000 cataract surgeries in North Korea. Using hidden cameras and footage shot while under the constant scrutiny of North Korean minders, Ling showcases life under Kim Jong Il, one of the world’s most absolute dictators.

The North Korean capital of Pyongyang is a virtual city, a showplace that nobody visits because visitors aren’t allowed. Ling shows us 12-lane highways that go virtually unused, apartment complexes for “defectors” from the West who never come and a hotel lobby sporting thousands of books, all written by Kim Jong Il’s father.

At one point, one of Ling’s photographers is nearly deported for photographing a statue of Kim from a disrespectful angle. We see a park bench enclosed in glass. Why? Because Kim Jong Il sat there once!

We visit an apartment where the walls are festooned with photos and posters — all of King Jong Il. When Ling asks her hosts which picture they prefer, the frightened folks don’t dare answer. They like them all.

“Inside” also features footage shot secretly by a German doctor on a humanitarian mission. The footage reveals mass starvation, nonexistent health care and an entire generation stunted by malnutrition.

¢ The History Channel follows up on its two-hour romp through the Dark Ages with a weeklong look at the barbarians who defined the era. Tonight’s rampaging hordes includes “The Vandals” (7 p.m., History). Let the sacking and pillaging begin!

¢ Hope springs eternal, and spring training brings hope to every baseball fan. Particularly Chicago Cubs fans, who have not cheered a World Series Champion since 1906. “REAL Sports with Bryant Gumbel” (9 p.m., HBO) sits down with Lou Pinella, the new manager of the Cubs, as he discusses his chances for ending this century-long drought.

Tonight’s other highlights

¢ Michael wants to confront the president on “Prison Break” (7 p.m., Fox).

¢ Howie Mandel hosts “Deal or No Deal” (7 p.m., NBC).

¢ Chris’ class presidency unravels on “Everybody Hates Chris” (7 p.m., CW).

¢ A married couple (Richard Dreyfuss and Bette Midler) adopt a homeless man (Nick Nolte) in the 1986 comedy “Down and Out in Beverly Hills” (7 p.m., AMC).

¢ Yonk suffers a heart attack on the season finale of “The Class” (7:30 p.m., CBS). “Class” dismissed.

¢ Frightening visions of tomorrow on “Heroes” (8 p.m., NBC).

¢ As the White House reels, Logan schemes on “24” (8 p.m., Fox).

¢ Making nice with Judith’s new friend on “Two and a Half Men” (8 p.m., CBS).

¢ A bad mother outsources her children to “Supernanny” (8 p.m., ABC).

¢ Russell revisits an old acquaintance on “Rules of Engagement” (8:30 p.m., CBS).

¢ After a supporter of an eminent-domain seizure is slain, a whole neighborhood falls under suspicion on “CSI: Miami” (9 p.m., CBS.

¢ With Sean in the hospital, Tommy takes action on “The Black Donnellys” (9 p.m., NBC).

¢ Laura gets bad vibes from Brian and Bridget on “What About Brian” (9 p.m., ABC).

¢ Ellen DeGeneres, Dr. Phil and Gwen Stefani appear on “Jimmy Kimmel Live” (11:05 a.m., ABC).

¢ Al Gore, Paul Giamatti and the Beastie Boys appear on “Late Night with Conan O’Brien” (11:35 a.m., NBC).