Great Migrations

To produce Great Migrations, a seven-hour documentary about animals in transit, filmmakers spent two and a half years in the field on 83 different shoots, covering 420,000 miles in 20 countries, on all seven continents.

"The show was born out of our mission to care about the planet," series producer David Hamlin says of the biggest multimedia project in the National Geographic Society's 122-year history, complete with a website (http://www.natgeotv.com/migrations), companion book and even an iPhone app. "With trillions of animals migrating every day out of a deeply motivated need to survive, we want to telegraph to the viewer that our encroaching footprint is dramatically affecting these creatures' journeys."

Narrated by 30 Rock's Alec Baldwin, each episode covers the astonishing and rarely recorded land, sea and air travels of species as large as sperm whales and elephants or as small as butterflies and phytoplankton. "There's drama, triumph, tragedy, elation and sadness in each of the stories we filmed," Hamlin says. "It's a gift from the natural world."

Great Migrations airs Sunday, 8/7c on National Geographic Channel.

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