In the far north of our planet lies the largest land habitat on earth, home to snow-covered forests and the icy open tundra. These are lands of extremes that push animals to their limits: in winter they are so cold that much of the ground has remained frozen since the last ice age. To stand any chance of survival, animals must adapt in extreme ways: here a super pack of wolves, 25 strong, has come together to take on the only large prey available to them in winter, American bison.
On the featureless tundra, an Arctic fox must strike a living alone. She is a wanderer and will roam many hundreds of miles searching for tiny lemmings, hidden deep underground. The only way to reach them is with a head dive. In the remote far east of Russia, a rare Amur leopard prowls the seemingly empty, snow-covered forest. With little prey available, it must use its ingenuity to find a meal. It follows crows in the hope of finding carrion, but it must not stay long, for it shares the forest with a far larger but equally hungry big cat, the Siberian tiger.
As spring arrives, the forests begin to thaw and life returns. Beneath the ground, a nest of tiny painted turtle hatchlings now emerge, having remained frozen in a state of suspended animation throughout winter. To the north, it is a further month before the sun’s warmth baths the frozen ground of the tundra. Tucked away underground lies a tiny snow queen – a Lapland bumble bee. She is the sole survivor of her colony - the rest perished in the winter freeze - but her larger size, her furry body and antifreeze in her blood have allowed her to survive. Now she is in a hurry. She must feed herself and raise a brood in the brief window of summer while the flowers are in bloom.
Snowy owls also use the open tundra to breed: one pair have raised a nest full of fluffy chicks. With 24-hour daylight in which to hunt, the dedicated parents bring back meal after meal for their ever-growing brood. But one day, they return to find the nest empty.
Today, the biggest challenge in the tundra is climate change. Warming summers are melting the permafrost deep within the soil, causing the ground to thaw and, in places, the land to collapse. These changes are impacting the animals too. Caribou arrive in herds of 200,000 individuals to raise their calves in the rich pastures, but warming means mosquitos emerge sooner and bother the calves before they have had a chance to gain strength. The parents drive their young to cooler, mosquito-free land, but to get there they must cross rivers running with increased meltwater and escape hungry grizzly bears. They, like much of the tundra's wildlife, are adapted to live in the extremes - but the challenge of today’s warming climate could be one extreme too many.

Mountains create frozen habitats on every continent on Earth, and each of these high-altitude worlds holds unique challenges for its surprising and remarkable life.
We begin our journey close to the equator - the furthest point from the poles - in East Africa. Here on the high slopes of Mount Kenya, during the day the tropical sun keeps the cold at bay, but at night the frost descends. During this cycle of freeze and thaw, a pregnant high-casqued chameleon must choose the right time to give birth if her newborns are to escape the deadly night freeze.
Away from the equator in the European Alps, long cold winters give way to short, bountiful summers. For a pair of golden eagles raising their chick, the demand to provide enough food for it drives them to tackle prey five times their size. To catch a goat-like chamois, they risk it all using one of the most daring and breathtaking hunting techniques ever witnessed.
The mountains of Japan are the snowiest place on Earth, providing hostile conditions for a lone male macaque cast away from his troop. His only chance of survival comes with finding another male whose embrace will provide him with life-saving warmth. But in the frozen peaks, the deadliest force is an avalanche whose full destructive power is captured for the first time using high-speed camera racer drones.
The roof of the world is home to an array of unexpected cold-loving creatures. In the remote Southern Alps of New Zealand, a species of parrot - the kea - uses its famed intelligence to feed on the dead. And in the Andes in South America, flamingos thrive in high-altitude volcanic lakes, but their chicks must race to escape the winter freeze or risk becoming trapped in the ice.
Today, due to climate change, our frozen peaks are undergoing rapid change. Using groundbreaking time-lapse photography, we reveal mountain glaciers vanishing before our very eyes and discover what a warming world may mean for our most famous mountain resident of all, the giant panda.

A young mother's mysterious death and her son's subsequent kidnapping blow open a decades-long mystery about the woman's true identity and the murderous federal fugitive at the center of it all.
It's late at night in Oklahoma City, in April of 1990. Two or three guys are in a truck driving along the road and they see some kind of debris. And then they see off to the side, there's a body. It appears to be a young woman, a blonde-haired woman and they call an ambulance. She's rushed to the hospital, and her husband, Clarence, eventually shows up. He says her name is Tonya Hughes, that she's a stripper in Tulsa, and that they have a young son named Michael. And he's much older and he's just kind of this weird guy. So, the doctors, as they continue to examine her, they see old bruises and old injuries. There's something wrong with this picture. Ultimately, she passes away. The girls Tonya danced with want to find her family. So they call this woman and they tell her that her daughter died. And she says, 'What are you talking about? My daughter died 20 years ago, she was only 18 months old.' They realize that who they just buried was not Tonya Hughes, so now they're asking, 'What happened?'.

Our super friends in the animal world possess so many hidden superpowers. In the third episode we meet heat-seeking dogs, GPS-outfitted cats, and a sporty goldfish with squad goals.
When we think we know them inside out, dogs surprise us with something new. what sensory superpower have dogs been hiding all this time? They have a thermal sensor in the tip of his nose. In the wild, a dog could use his thermal nose to spot the heat of a prey animal, allowing him to hunt even if his other senses were impaired. It also explains that uncanny knack for stealing a warm seat.

The film documents the English heavy metal band Black Sabbath's final show of their farewell concert tour, The End Tour. The performance was held at the Genting Arena in Birmingham, England, hometown of the band's founding members: vocalist Ozzy Osbourne, guitarist Tony Iommi, bassist Geezer Butler, and drummer Bill Ward. Osbourne, Iommi, and Butler performed this final concert with session drummer Tommy Clufetos in place of Ward, as well as Adam Wakeman on keyboards and guitar.
The concert opens with a performance of the song 'Black Sabbath'. The film goes on to show the band performing 'Fairies Wear Boots', 'Under the Sun/Every Day Comes and Goes', 'Into the Void', 'Snowblind', 'War Pigs', 'Hand of Doom', 'Iron Man', and 'Children of the Grave'; at the end of the setlist, the band performs the song 'Paranoid' as an encore.
Interspersed with the final concert are interviews with Osbourne, Iommi, and Butler, in which they talk about their careers and past drug addictions. Additionally, Iommi's 2012 lymphoma diagnosis, which impacted the band's 2012–14 reunion tour and the recording of their 2013 album 13, is discussed. The film also features footage of 'The Angelic Sessions'—the band's final studio recordings, which took place in the days following the final show. Of these recordings, the film shows Osbourne, Iommi, and Butler performing 'The Wizard', 'Wicked World', and 'Changes'.

Even as the science grew more certain, the oil industry continued to block action to tackle climate change in the new millennium. In a revelatory interview, Christine Todd Whitman, George W. Bush's former environment chief, tells the story of how the industry successfully lobbied President Bush to reverse course on his campaign promise to regulate carbon emissions.
Tensions grew between two of the world's biggest oil companies, ExxonMobil and BP, after the latter publicly called for action to tackle climate change. The election of Barack Obama provided hope for supporters of climate action, but the billionaire Koch brothers made an effort to block the new president's attempts to pass climate change legislation, and climate denialism became the mainstream position of the Republican Party. A lawyer who worked for Koch brothers through this period speaks on camera for the first time.