Sir David Attenborough explores the surprisingly vibrant seas that surround the British Isles. The vast watery wilderness around us is over three times the size of our land mass, and yet to many, our oceans remain a mystery. Full of colour and teeming with life, the seas of Britain and Ireland are crucially important to a range of wildlife. This episode goes beneath the waves to uncover the thriving habitats that exist along our 22,000-mile coastline.
In winter, clear evidence of the ocean’s abundance can be seen on a beach in Norfolk. Thousands of grey seals congregate on the shoreline to give birth. Britain and Ireland are home to 40 per cent of the world’s grey seals, and the number being born on our shore rises every year. Once the newly born pups are weaned, the females are ready to breed again, and heavyweight males enter violent, bloody fights to win a stretch of beach, and the females along with it.
Beyond the beach, the vibrant shallows contain several important habitats. Rich beds of seagrass are nurseries for a range of animals, while also acting as very important carbon storage areas. They are also home to one of the strangest fish in our waters, the seahorse. We follow a male and female as they perform a balletic mating dance in the water, delicately entwining their tails. The stakes are high, as these animals mate for life.
In a touching piece to camera, Sir David bids a fledging Manx shearwater chick farewell as it embarks on a 6,000-mile journey across the oceans to South America. There is no better example of how important the British Isles and its abundant seas are to the survival of wildlife worldwide.

600 miles off the coast of South America in the Pacific Ocean there are 120 tropical islands that erupted from the deep ocean floor more than 10 million years ago. Journey from the lava ramparts to its fiery heart, we'll discover how the Galapagos archipelago became one of the most important areas of biodiversity in the world.
Those swept here by storms and currents survived million to one odds to find untouched islands free from competition. These hardy pioneers evolved in remarkable ways in what's known as Nature's Greatest Experiment. Home to bizarre specialists and unexpected giants, the most precious collection of island creatures on Earth.

At the far tip of South America, lies a magical realm that seems frozen in time. Known as 'the end of the world', this is Patagonia. Vast glaciers shaped it into an Eden like no other. Adaptable and resilient creatures evolved unique survival strategies to flourish across its remarkable habitats. From precipitous mountain citadels and icy desert plateaus windswept steppe uplands through remote, primal forests to a mosaic of glacial valleys. To thrive here is to be as extreme as the land itself.

Ewan, Charley, and the team land in Ushuaia, the southernmost tip of South America, but tensions arise due to snow and mechanical issues. Traveling 13000 miles over 100 days on electric bikes is hard to imagine. Ewan McGregor and Charles Boorman find out how challenging their mission is as they embark on a journey on prototype Harley Davidsons and the Rivian trucks. The first obstacle is electricity. While parts of the city have no problems with charging the bikes and the trucks, the countryside is where the duo face issues.

A jaguar fights to keep his river home in Brazil as the night brings both challenges and opportunities to hunt. Evening is falling in the world's greatest tropical wetland, Brazil's Pantanal. A stronghold for South America's most secretive big cat, the jaguar. And enjoying the last warmth of the day is a male known as Juru. At six years old and weighing over 100 kilos, he's amongst the largest, most powerful big cats in the Americas. This prime stretch of river has been his territory for two years. But tonight Juru's reign hangs in the balance. In a recent fight with a rival male, he badly injured his paw. It's left him weak and hungry. The coming days and nights will test him more than ever before. He'll need to summon the strength to defend his river.

In 1799, the German scientist Alexander von Humboldt embarked on a perilous journey of discovery across South America. It would take him to the deepest jungle near the Orinoco and to the heights of the Andes. His aim was twofold: to conduct the first scientific survey of South America and to discover how the natural world actually works — at a time when most scientists believed that the world was created less than 6,000 years ago. He later became a leading scientific figure and champion of the abolitionist movement in the US.
This extremely visual docudrama follows Humboldt’s extraordinary path. Travelling in Humboldt’s footsteps is historian Andrea Wulf, whose book on Humboldt became a worldwide bestseller. For good reason, since Humboldt’s ideas on the planet’s fragile web of life are as important today as they were 220 years ago.