The contests between predators and prey are the most dramatic events in nature. Taking an intimate and detailed look at the remarkable strategies employed by hunters to catch their prey and the hunted to escape. Sir David Attenborough narrates. "The Hardest Challenge" reveals the extraordinary range of techniques predators use to catch their prey - from a leopard using all its powers of stealth to stalk impala in broad daylight to wild dogs, whose tactic is to wear down their prey over long distances; from Nile crocodiles, the planet's most patient predators, to killer whales who use teamwork and intelligence to take on humpback whales. But even with these finely tuned strategies, the outcome is far from certain. Surprisingly, most predators fail most of the time.

The stunning beauty of an island paradise on a quest to find the perfect wave-riding experience. Nine-time world surfing champion Kelly Slater and Tahitian surfer Raimana Van Bastolaer and a group of friends seek out the best waves breaking on the reef at Tahiti's famed surf site Teahupo'o. As their quest unfolds, the audience is plunged beneath the surface of things, to explore the hidden forces at work shaping ocean waves and the islands that lie in their path. Amidst playful surfing action, we navigate the cosmos and an ocean storm in a search for the source and nature of a wave's energy. Exploring mountainous Tahiti, we are thrust into the turbulent volcanic past of the island and its neighbours and discover the seagoing, wave-riding roots of the islanders themselves -- a culture still rich in the music, dance and lore of the sea. Beneath the ocean, swimming with our surfers, we explore the stunning, fragile beauty of the reef habitat -- a turbulent, wave-shaping interface that envelops the island and nurtures the ocean's multitudes in motion -- fish, dolphins, sharks and whales. When the truly big surf arrives at Teahupo'o, surfing play becomes surfing survival as the riders artfully tackle some of the heaviest surf on the planet -- spectacularly captured for the giant screen in 3D for the first time.

Every year, around the world, seasonal changes transform entire landscapes and draw in millions of creatures as these great events unfold. This fantastic series combines the epic scale of Planet Earth and the intimate, emotional stories of charismatic animals as they struggle to survive. Using state of the art technology, these programmes capture the Earth's most dramatic and epic wildlife spectacles and the intimate stories of the animals caught up in them.
The Great Melt: The summer melt of Arctic ice, opening up nearly three million square miles of ocean and land, provides opportunities for millions of animals, including beluga whales, families of Arctic foxes, vast colonies of seabirds, and the fabled Arctic unicorn, the narwhal. For polar bears, however, it is the toughest time of year. Why? How will they survive? A mother polar bear and her cub make their first journey together onto the sea ice. They are looking for ringed seals, their favourite prey. It is a serious business but the cub just wants to play. The melting ice makes it harder for them to hunt and threatens their survival. In a unique aerial sequence, the migration of narwhal with their distinctive unicorn-like tusks is filmed for the first time. The whales' journey is risky as they travel along giant cracks in the ice. If the ice were to close above them, they would drown. Hundreds of beluga whales gather in the river shallows. They rub themselves on smooth pebbles in one of the most bizarre summer spectacles. Guillemot chicks take their first flights from precipitous sea cliff nests to the sea 300 metres below. They attempt to glide to safety but many miss their target. Their loss is a bonus for the hungry Arctic fox family waiting below. As the melt comes to an end the bears gather, waiting for the sea to freeze again. Two 400kg males square up to each other to spar.

Mammals dominate the planet. They do it through having warm blood and by the care they lavish on their young. Weeks of filming in the bitter Antarctic winter reveal how a mother Weddell seal wears her teeth down keeping open a hole in the ice so she can catch fish for her pup. A powered hot air balloon produces stunning images of millions of migrating bats as they converge on fruiting trees in Zambia, and slow-motion cameras reveal how a mother rufous sengi exhausts a chasing lizard. A gyroscopically stabilised camera moves alongside migrating caribou, and a diving team swim among the planet's biggest fight as male humpback whales battle for a female.

A dramatic journey along the coasts of South America, from the Falklands to the tropical Galapagos. The cold currents create rich fisheries, and support such diverse marine life as dolphins, killer whales, sea lions and albatross. But the most biquitous creatures are the penguins, which inhabit surprising locations - lush forest, arid desert and even equatorial areas.

The idea of intelligence is explored in the concepts of computers (using bits as their basic units of information), whales (in their songs and their disruptions by human activities), DNA, the human brain (the evolution of the brain stem, frontal lobes, neurons, cerebral hemispheres, and corpus callosum under the Triune Brain Model), and man-made structures for collective intelligence (cities, libraries, books, computers, and satellites). The episode ends with speculation on alien intelligence and the information conveyed on the Voyager Golden Record.