Making Planet Earth

One memorable scene captures a bird's-eye view of a polar bear swimming between large chunks of ice in the ocean. "Polar bears spend a lot of time on the sea ice, and I was lucky enough to be flying in a helicopter above this male polar bear. Beautiful image—dark blue sea, broken ice, and this bear was out there," Alastair says.

In order to capture close-up images of polar bears swimming, Alastair says the cameramen had to use extra precautions and special equipment—or they could end up as lunch! "Polar bears can only feed for two or three months of the year, and the rest of the time they're really hungry," he says. "And a nice fat cameraman is a good meal for a polar bear."

Alastair says these beautiful images are even more powerful because of the problems global warming causes for polar bears. Some believe, he says, the animals could be extinct by 2030. "The polar bear … is completely relaxed, but he was in trouble. You know, polar bears don't like to swim. And increasingly, as this polar ice melts, they're having to swim more and more," he says.