Once funding was set for the wildly ambitious and groundbreaking BBC nature documentary "Planet Earth," a rich portrait of our vibrant and sometimes strained ecosystem on DVD this week, the makers of the series couldn't have been more excited.

But first on the agenda for one of the series' producers, nature documentary veteran Vanessa Berlowitz, was a personal issue: With the whole world up for grabs, who got to go where?

"Obviously, there's going to be deserts, seas, whatever, so the producer asks, 'Who wants to make what?' " Berlowitz recalls. "Then everyone scrambles around going, 'I want this! I want that!' In reality, our skill sets tended to fall quite naturally into some of the films. ..."

By Hollywood standards, "Planet Earth" was made for a pittance, around $40 million. But by documentary standards, that figure is nearly unprecedented, and the producers put it to good use traversing the globe and recording sights and events never before caught on film, let alone in stunning high definition.

From the oceans to the deserts to the forests to the mountains, "Planet Earth" depicts our home like few ever have seen it before. What viewers don't get to see, however, is all the work that went into getting those spectacular shots, which ranged from practical problem solving to political tightrope walking.

"A lot of the best wildlife in the world is often, ironically, in war zones," Berlowitz notes. "I don't know why that is. I looked at my filming list for 'Mountains' and I had Nepal and Pakistan on there. Nepal was in the middle of a Maoist insurgency, and Pakistan, as you know, there are continuing issues there. Because the area of Pakistan is 50 kilometers from the border of Afghanistan, it's an implicitly unstable area. We had to wait a year, a year of planning and heavy risk assessment with the BBC. Could we justify the risk of sending in a wildlife team? I didn't want to send in a team and jeopardize their lives, however important it was to film snow leopards."

Just as important was the reality of climate change, which made its presence apparent throughout filming.

"When I was out on the Arctic, looking at the polar bears struggling on the ice, I was hit by this feeling, 'Oh, my God, am I recording an image that simply the next generation won't get to see?' Over five years, we documented climate change, what's actually happening out there on the real front line of climate change. It was a problem. Migrations weren't happening at the right time. Weather conditions were unpredictable. Things we were told were guaranteed to happen didn't."