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.

The world of invertebrates exists in a web of relationships with plants and other animals. Unique footage of the world's smallest insect (a fairy wasp only quarter of a millimetre long) shows it flying underwater to find the eggs of water beetles in which to lay its own brood. Some ants 'farm' the trees that give them shelter, creating areas known as 'Devil's gardens'. To make sure these grow without competition, they kill off other seedlings in the surrounding vegetation. The blister beetle's larvae huddle together on the end of a piece of grass and mimic a female bee. When a male bee tries to mate with the 'female', the larvae grab on to his belly. Confused, he flies away and searches for a real female. When he eventually finds her and mates with her, the beetle larvae hurriedly swap from his front on to her back, and hence get carried back to her nest where they eat her pollen supplies.

In this second episode we travel from January to the March equinox. Kate Humble gets closer to the Sun than she has ever been before, whilst Helen Czerski visits a place that gets some of the biggest and fastest snowstorms on Earth.

Seafood is a substantial part of the daily diet of over three billion people and oceans absorbs almost a third of all the greenhouse gases we emits. Buy the ocean it is not what it once was. Scenes of extraordinary ocean abundance now only exist in far-off places or in tales from the past. We urgently need to mend our relationship with our oceans and allow them to thrive once again.
Prince William, David Attenborough and Shakira find out about inspiring people and projects across the world that can help us stop damaging the oceans and enable their revival.

Jeremy Clarkson decides to become a naturalist. 'In just 30 years, insect numbers have dropped by 25% and they're still falling. Without insects, all life on Earth ends. Everywhere where insects like to live is disappearing and I've decided to do something about that. My plan is to make my hedgerows, my valleys, my woods, and my streams more attractive to creepy crawlies. In essence, I am going to leave chunks of the farm completely alone. I'm going to put Mother Nature in the driving seat. It's a process called wilding.'

Stephen Hawking, the world's most famous living scientist explores the greatest mysteries of the cosmos. In three landmark instalments he reveals the wonders of the universe as never seen before. Definitive, provocative, surprising, and beautiful, Into the Universe with Stephen Hawking is a fascinating look through the mind's eye of one of the finest brains on the planet. In 'Aliens' Hawking considers one of the most important mysteries facing humankind - the possibility of alien, intelligent life. He leads us on a journey rendered in eye-popping detail, from the moons of Jupiter to a galaxy maybe not so far, far away. We will meet possible aliens and wonder at their form, we will delve into the very principles of what it is to call something alive, and we will calculate the likelihood of 'contact' being made.