Most planets we know of are so hellish, it seems impossible that anything could live. But it's amazing where life can take hold in the Earth. Astrobiologists look for simple single-celled microbes known as extremophiles in places as Danakil Depression, known in Ethiopia as 'The Gateway to Hell.'
In Episode 2, the fictional world is Janus, a planet in such a close orbit than its rotation is locked by the star's gravity and it always shows the same face to its sun. On one side of the planet, it's always daytime, a searing desert. On the other side, it's forever night, a frozen shadowland. Squeezed between the two, a sliver of perpetual twilight. Freezing meltwater flows from the cold side, carving canyons through the landscape. Deep in these canyons lives an extraordinary five-legged creature.

An exploration of active volcanoes in Indonesia, Iceland, North Korea and Ethiopia, Herzog follows volcanologist and co-director Clive Oppenheimer, who hopes to minimize the volcanoes’ destructive impact. What is the Herzog’s quest? To gain an image of our origins and nature as a species. He finds that the volcano—mysterious, violent, and rapturously beautiful—instructs us that, "there is no single one that is not connected to a belief system".

The sixth and last episode of the series follows photographer Art Wolfe as he documents the world's cultures, including the Surma of Ethiopia and the masked mud men and Huli clans of Papua, New Guinea.

Professor Brian Cox examines how it was that in a universe made of stars, rocks and endless space, a conscious civilisation was born. His latest adventure takes him from a submerged space station in Star City on the outskirts of Moscow, to Ethiopia, high above in the Great Rift Valley, where he encounters the geladas, mankind's distant ancestors. Despite once being Africa's most successful primate, a species who at one time roamed across the entire continent, these days they are found in one just place in the remote Ethiopian Highlands. Cox investigates why these ancestors retreated, yet modern mankind has expanded across the planet.

From lush cloud forests to bare summits that take your breath away, the higher you climb the tougher life gets on a mountain. Human Planet explores the extraordinary ways in which people survive at extreme altitudes where nature becomes utterly unforgiving. In the Altai Mountains in Western Mongolia the vast open spaces make hunting for animals almost impossible, so the locals have forged an astonishing partnership with golden eagles which can do the hunting for them. On the precipitous cliffs of the Simien Mountains of Ethiopia we join a young boy locked in a dramatic battle with fearsome gelada monkeys which are hell-bent on raiding his family's meagre grain harvest. In the Himalayan state of Nepal - the roof of the world - we witness a rarely seen ceremony: a sky burial. In a land where there is little wood to burn for cremation, and where burying the dead is virtually impossible, the dead are fed to vultures in the ultimate reverence of nature.

Birds owe their global success to feathers - something no other animal has. They allow birds to do extraordinary things. For the first time, a slow-motion camera captures the unique flight of the marvellous spatuletail hummingbird as he flashes long, iridescent tail feathers in the gloomy undergrowth. Aerial photography takes us into the sky with an Ethiopian lammergeier dropping bones to smash them into edible-sized bits. Thousands of pink flamingoes promenade in one of nature's greatest spectacles. The sage grouse rubs his feathers against his chest in a comic display to make popping noises that attract females. The Vogelkop bowerbird makes up for his dull colour by building an intricate structure and decorating it with colourful beetles and snails.