Every year, over a thousand climbers try to reach the summit of Mount Everest, with the annual record for successful attempts currently standing at 633. But of that number, nearly half were Sherpas - the mountain's unsung heroes. Yet the Sherpa community has remained secretive about their nation, culture and experiences living in the shadow of the world's highest mountain. Now, for the first time, they open the door into their world. Without the expertise of the Sherpas, only the hardiest and most skilful climbers would succeed. Every day they risk their lives for the safety of others, yet they seek neither glory nor reward, preferring to stay in the background. Following the stories of four such Sherpas - Phurba, Ngima, Ngima Tenji and Gelu - this film reveals the reality of their daily lives, not just up the mountain, but with their families after they return home.

Morgan Freeman narrates Island of Lemurs: Madagascar, the incredible true story of nature's greatest explorers - lemurs. Scientist Patricia Wright has a passion for preserving the life of one particular creature: the lemur. These lively animals found in Madagascar face all sorts of threats, just like so many other animals in a world in which they are increasingly crowded out by humans. Her passion for the subject is compelling and plainly evident, but it's the silent testimony of the animals themselves that really makes the case. Countless hours of footage are trimmed down to create this tapestry depicting the lives of these creatures of remarkable intelligence and ingenuity. Their daily routines and extraordinary adventures are awesome to behold, as is the way that the community functions. A full immersion into the world of the lemurs means great insights on these unusual animals.

Enjoy this wonderful documentary from Disney Nature about a family of brown bears living in the coastal mountain ranges of Alaska." A brown bear mother named Sky gives birth to two cubs named Amber and Scout in her den on a mountain slope. When April comes the bears will be ready to leave the den. As the bears leave the oncoming summer brings with it a threat of avalanches. Fortunately the bears are able to avoid disaster. Upon reaching the lush valley below, the cubs meet the other bears, some of which pose a threat to the cubs; among these bears are Magnus, a big healthy male, and Chinook, an older male. The family works together to survive the spring, with Sky keeping the cubs safe from Tikaani, a pesky grey wolf...

A group of brave individuals risk their lives to save the last of the world's mountain gorillas; in the midst of renewed civil war and a scramble for Congo's natural resources." Virunga National Park in the Congo is a place of unique natural beauty. It is the home to a plethora of wonderful animals and vegetation but as is so often the way, it has several serious problems that threaten it. It's the location of human violence, corruption and exploitation. The disasters that specifically loom are two different groups, the M23 and SOCO International. The former are a violent rebel force who engages in an ongoing civil war with the Congolese government and the latter are a British energy company who specialise in oil exploration. Both M23 and SOCO invade the park in their own ways and neither seems very interested in the laws that have been set up to protect the flora and fauna that exist there, far less the people who live there. It seems hardly surprising in the case of M23, as they are a paramilitary organisation who can hardly be expected to be concerned with such things but it is the more legitimate big business SOCO who seem more worrying if anything. We discover in fact that they have been involved in a bribery campaign, utilising M23 as enforcers. It's a very murky situation where big money walks all over an impoverished nation and disregards a natural space that they can see no value in in their pursuit of financial profit.

In this final episode we complete our journey, travelling back from the March equinox to the end of June. Kate Humble is in the Arctic at a place where spring arrives with a bang, whilst Helen Czerski chases a tornado to show how the earth's angle of tilt creates the most extreme weather on earth.

'Deliver Us from Drought' - Over the past years, Texas has experienced the worst drought in its recorded history. 97% of the scientific community agrees that human activity has contributed to extreme weather patterns around the world. But many Texans--legislators, community leaders and citizens--don't attribute their drought to humans, and have taken few if any initiatives to limit the state's CO2 emissions, currently the highest in the country. "The Resource Curse" - As humanity's appetite for energy grows exponentially, the extraction industry scrambles to the most remote regions on Earth. In the undeveloped Melanesian country of Papua New Guinea, America's Exxon Mobil has staked its claim to a $19 billion liquid natural-gas project. While some see Exxon's mammoth presence as the catalyst that will usher the underdeveloped country into the 21st Century, others predict the initiative could plunge its people into civil war.