The series comprises eleven episodes, each of which features a global overview of a different habitat on Earth. At the end of each fifty-minute episode, a ten-minute featurette takes a behind-the-scenes look at the challenges of filming the series.
But with the second three episodes, I think they kicked things up a notch. Maybe it's the subject matter, but these episodes are almost consistently spectacular. Some highlights:
People on Planet Earth
The first three episodes show nothing manmade except a small helicopter in one mountain shot. But starting with Caves, Planet Earth seems more willing to acknowledge the presence of humans. Perhaps it's the fact that you can't grasp the size of underground caverns without tiny persons in the pictures.
In the Diaries portion of Deserts, we meet the indigenous Mongolians who led the film crew to the few remaining wild Bactrian camels. More to the point, the Caves episode tells us how the Maya were unique among civilizations. They had no rivers, so they got their water from cenotes--huge well-like reservoirs fed by the underground system of water-filled caverns.
The episode even shows a Maya pyramid--by far the largest human artifact seen on the series. In short, Caves gives us the first and--so far--only example of how humans interact with and depend on their environment.
I wasn't going to recommend Planet Earth, but now I will. You should check it out, especially if you have children. Renew your appreciation of the wonders of nature.
For more on the subject, see Inuit in Arctic Tale and Native Documentaries and News.