Sigourney Weaver narrates Planet Earth.Discovery Channel/Todd Plitt - Thursday, March, 1, 2007, 10:1 PM

Underwater cameraman Doug Allan films mother and baby humpback whales off Tonga in the South Pacific as seen on Planet Earth.Discovery Channel/BBC/Sue Flood - Thursday, March, 1, 2007, 10:1 PM

Cameraman Paul Stewart with Huli tribes people in Papua New Guinea as seen on Planet Earth.Discovery Channel/Tom Clarke - Thursday, March, 1, 2007, 10:1 PM

Glacier National Park from helicopter. Cameraman Mike Kelem prepares the Heli-Gimble Camera as seen on Planet Earth.Discovery Channel/Jean-Marc Gibuox/Getty Images - Thursday, March, 1, 2007, 10:1 PM

Cameraman filming in flooded caves in the Yucatan, Mexico as seen on Planet Earth.Discovery Channel/Gavin Newman - Thursday, March, 1, 2007, 10:1 PM

Stalactites cave in Wales, UK as seen on the 'Caves' episode of Planet Earth.Discovery Channel/BBC - Thursday, March, 1, 2007, 10:1 PM

Baobab trees in Madagascar, as seen on the 'Forests' episode of Planet Earth.Discovery Channel/Warwick Sloss - Thursday, March, 1, 2007, 10:1 PM

Tigress coming around tree {Panthera tigris tigrist} in Rajasthan, India, as seen on the 'Forests' episode of Planet Earth.Discovery Channel/Anup Shah - Thursday, March, 1, 2007, 10:1 PM

World's highest waterfall, Angel Falls, in Venezuela, as seen on the 'Fresh Water' episode of Planet Earth.Discovery Channel/Mark Brownlow - Thursday, March, 1, 2007, 10:1 PM

Male Superb Bird of Paradise (seen from the front) performing courtship display to female in a rainforest, Papua New Guinea, as seen on the 'Jungle' episode of Planet Earth.©Discovery Channel/BBC - Thursday, March, 1, 2007, 10:1 PM

Fungus on rainforest floor, as seen on the 'Jungle' episode of Planet Earth.Discovery Channel/Tom Hugh-Jones - Thursday, March, 1, 2007, 10:1 PM

Lions hunting African elephants in Savute National Park, Botswana, as seen on the 'Great Plains' episode of Planet Earth.Discovery Channel/BBC/Ben Osborne - Thursday, March, 1, 2007, 10:1 PM

Kiang wild ass, Tibet (Equus kiang), as seen on the 'Great Plains' episode of Planet Earth.©Discovery Channel/BBC/Jonny Keeling - Thursday, March, 1, 2007, 10:1 PM

Wildebeest herd (Connochaetes taurinus) grazing on savanna, Masai Mara Game Reserve, Kenya, as seen on the 'Great Plains' episode of Planet Earth.Discovery Channel/BBC/Anup Shah - Thursday, March, 1, 2007, 10:1 PM

Lions hunting elephants as seen on the 'Great Plains' episode of Planet Earth.Discovery Channel/BBC - Thursday, March, 1, 2007, 10:1 PM

Aerial view of flooded Okavango delta, Botswana as seen on the 'Great Plains' episode of Planet Earth.Discovery Channel/Ben Osborne - Thursday, March, 1, 2007, 10:1 PM

Cameraman Wade Fairley films emperor penguins in Antarctica as seen on Planet Earth.Discovery Channel/BBC/Frederique Olivier - Thursday, March, 1, 2007, 10:1 PM

Icebergs with Emperor penguins (Aptendytes forsteri), as seen on the 'Frozen' episode of Planet Earth.Discovery Channel/BBC/Fred Olivier - Thursday, March, 1, 2007, 10:1 PM

Polar bear cubs following mother on ice (Ursus maximus) Hudson Bay, Canada, as seen on the 'Frozen' episode of Planet Earth.Discovery Channel/BBC/Terry Andrewartha - Thursday, March, 1, 2007, 10:1 PM

Best Shows of '06-'07: Planet Earth: Nature's beauty blows us away.Discovery Channel/Sue Flood - Thursday, March, 1, 2007, 10:1 PM

Iceberg with aurora southern lights as seen on the 'Frozen' episode of Planet Earth. Discovery Channel/Fred Olivier - Thursday, March, 1, 2007, 10:1 PM

Portrait of five male elephants walking by a mountain of sand, as seen on Planet Earth.Discovery Channel/BBC - Thursday, March, 1, 2007, 10:1 PM

Yardang rock formation, Egypt, as seen on the 'Desert' episode of Planet Earth.Discovery Channel/BBC - Thursday, March, 1, 2007, 10:1 PM

Sand storm, as seen on the 'Desert' episode of Planet Earth.Discovery Channel/BBC - Thursday, March, 1, 2007, 10:1 PM