It's billed as the ultimate portrait of our planet.Discovery Channel's "Planet Earth" is an 11-part series with the ultimate global view. Five years in the making, it boasts 200 locations with more than 70 camera operators having spent 2,000-plus days in the field to document nature's wonders.

Among the series' countless never-before-filmed moments: a polar bear clambering from her snow-covered Arctic den, trailed into the dawn by her pair of cubs.

Narrated by Sigourney Weaver, "Planet Earth" begins at 9 p.m. tomorrow with three episodes:

[bul] "Pole to Pole," which follows the sun as it touches the lives of creatures across the planet, shedding light on how the world is interconnected.

[bul] "Mountains," which tours Earth's mightiest mountain ranges to meet the rare animals that inhabit them.

[bul] "Deep Ocean," which investigates the waters that cover two-thirds of the Earth's surface yet remain largely unknown.

Future episodes cover such habitats as jungles, caves and "Ice Worlds."

Shot in high definition, the eye-popping "Planet Earth" airs weekly through April 22.

Other shows this week to look out for>

[rt] Lifetime network confronts the problem of binge drinking among youth in its film, "The Party Never StopB>, the story of a college freshman who falls prey to newfound temptations. Former high school track star Jesse is thrilled to be away from home and her mom, and hits it off instantly with her new roommate.

But their innocent partying soon gets out of control, and they find themselves sucked into a lifestyle of skipping classes, failing grades and lying to their parents to cover up their drinking. The film reflects statistics that indicate about 90 percent of the alcohol consumed by youth under the age of 21 in the US is in the form of binge drinking (defined as more than four drinks for men or more than three for women within a two-hour period).

The film, which stars Nancy Travis, Chelsea Hobbs and Sara Paxton (as Jesse), airs on Monday at 10 p.m.

[rt] In summer 2006, a bus full of Iranian pilgrims left Tehran on a five-day journey to the holy city of Karbala, deep inside a shattered Iraq. PBS' "Wide Ang follows this harrowing journey into the heartland of Shia Islam, revealing how two ancient crimes — the murder of Muhammad's grandson and the disappearance of a 6-year-old imam — became the founding legends of Shiism and increasingly dominate events in the Middle East today.

Under Saddam Hussein's rule, it was impossible for Iranians to make the pilgrimage to Karbala, but since his overthrow, Shia Muslims, who dominate Iran and are the majority in Iraq, can now make the trek. It is dangerous, but their faith is stronger than their fears. "Pilgrimage to Karbala" shows how, premiering 11 p.m. on Monday.

[rt] "Childhood Obesity: Danger Zo addresses a growing epidemic that grips more than 12 million US children and teenagers. In the past 40 years, childhood obesity has quadrupled, affecting 17 percent of the youth population with what could be the silent killer of a new generation: According to the programme, half of the youngsters diagnosed with obesity suffer from hypertension, gastrointestinal problems and other health threats. Besides highlighting the problem, the hourlong special also shows how parents can serve as agents of change in their child's life, and what communities can do at a public health level. Produced by Al Roker, it airs at 10 p.m. today on the Food Network.

[rt] Directed by Kirby Dick, the acclaimed documentary "This Film Is Not Yet Rd" asks whether Hollywood movies and independent films are rated equally for comparable content; whether sexual content in gay-themed movies are given harsher ratings penalties than their heterosexual counterparts; whether it makes sense that extreme violence is treated more forgivingly than extreme sexuality.

The film — which in part is about Dick's own efforts to get a rating for this film — has its television premiere 11 p.m.Saturday on the Independent Film Channel.