David Attenborough: "A hundred years ago, there were one and a half billion people on Earth. Now, over six billion crowd our fragile planet. But even so, there are still places barely touched by humanity. This series will take you to the last wildernesses and show you the planet and its wildlife as you have never seen them before."

"From Pole to Pole" - During Antarctica's winter, emperor penguins endure four months of darkness, with no food, in temperatures of minus 70°C. The forests of eastern Russia are home to the amur leopard: with a population of just 40 individuals, it is the world's rarest cat. However, in the tropics, the jungle that covers 3% of the planet's surface supports 50% of its animals.
"Mountains" - Ethiopia's Erta Ale is the longest continually erupting volcano — for over 100 years. Grizzly bear cubs emerge from their den for the first time in the Rockies, while Himalayan inhabitants include the snow leopard, rutting markhor and golden eagles that hunt migrating demoiselle cranes.
"Fresh Water" - Only 3% of the world's water is fresh, yet all life is ultimately dependent on it. The erosive nature of rivers is shown by the Grand Canyon, created over five million years by the Colorado River. In Japan, the water is inhabited by the biggest amphibian, the two-meter long giant salamander, while in the northern hemisphere, salmon undertake the largest freshwater migration, and are hunted en route by grizzly bears.
"Caves" - Mexico's Cave of Swallows is, at 400 meters, the Earth's deepest, and diving into it is akin to jumping off New York City's Empire State Building. In addition, there are glimpses of a number of subterranean, eyeless creatures, such as the Texan cave salamander and even a species of crab.
"Deserts" - Due to Siberian winds, Mongolia's Gobi Desert reaches extremes of temperature like no other, ranging from -40°C to +50°C. Africa's Sahara is the size of the USA, and just one of its severe dust storms could cover the whole of Great Britain: for some creatures, the only escape from such a bombardment is to bury themselves in the sand. The final sequence illustrates one of nature's most fearsome spectacles: a billion-strong plague of desert locusts, destroying all vegetation in its path.