Comet ISON can well be the brightest and most spectacular comet for a generation. It appeared above the eastern horizon from December 2013 as a glorious streak across the sky. ISON has been travelling towards the sun for ten thousand years and will make only one orbit through its corona before disappearing off into the outer solar system.
But as well as providing a great spectacle, ISON's tail of vaporised gas and water, hundreds of millions of kilometres long, will give insights into some of the greatest mysteries of science; it will help explain the origins of the solar system, whether earth's water was delivered on comets and even whether we are alone in the universe.

The great flood in the Okavango turns 4,000 square miles of arid plains into a beautiful wetland. Elephant mothers guide their families on an epic trek across the harsh Kalahari Desert towards it, siphoning fresh water from stagnant pools and facing hungry lions. Hippos battle for territory, as the magical water draws in thousands of buffalo and birds, and vast clouds of dragonflies. Will the young elephant calves survive to reach this grassland paradise? The experienced mother elephants time their arrival at the delta to coincide with the lush grass produced by the great flood.
In a TV first, the programme shows the way they use their trunks to siphon clean water from the surface layers of a stagnant pool, while avoiding stirring up the muddy sediment on the bottom with their feet. Lechwe swamp deer, zebras, giraffes, crocodiles and numerous fish and thousands of birds arrive in the delta. And, in a phenomenon never before filmed in the Okavango, thousands of dragonflies appear - seemingly from nowhere - within minutes of the flood arrival, mating and laying eggs. As the flood finally reaches its peak, elephants and buffalo, near the end of their epic trek across the desert, face the final gauntlet of a hungry pride of lions. In a heart-wrenching sequence, a baby elephant is brought down by a lion in broad daylight.

Sir David Attenborough takes a breath-taking journey through the vast and diverse continent of Africa as it's never been seen before. From the richness of the Cape of Good Hope to blizzards in the high Atlas Mountains, from the brooding jungles of the Congo to the steaming swamps and misty savannahs, Africa explores the whole continent. An astonishing array of previously unknown places are revealed along with bizarre new creatures and extraordinary behaviours. Using the latest in filming technology including remote HD cameras, BBC One takes an animal's eye view of the action. The journey begins in the Kalahari, Africa's ancient southwest corner, where two extraordinary deserts sit side by side and even the most familiar of its creatures have developed ingenious survival techniques. Black rhinos reveal a lighter side to their character as they gather around a secret waterhole. Springbok celebrate the arrival of rains with a display of 'pronking'. Bull desert giraffes endure ferocious battles for territory in a dry river bed.

Could we get all our energy needs from sea water and the salt it contains? Are we to witness a time when salt will power our engines and factories, and light up our cities? Could this be the final curtain not only for shale gas and oil, but also the burning of fossil fuels and the beginning of a gentler form of energy that is definitely renewable? This documentary explores the latest research on sea water and the way scientists all over the world are working on 'Blue Energy'. This research could bring about a major change in our time.

An extraordinary journey to the top of the world, the documentary adventure tells the ultimate tale of survival. The film takes audiences on a never-before-experienced journey into the lives of a mother polar bear and her twin seven-month-old cubs as they navigate the changing Arctic wilderness they call home. Captivating, adventurous and intimate footage brings moviegoers up close and personal with this family's struggle to survive in a frigid environment of melting ice, immense glaciers, spectacular waterfalls, and majestic snow-bound peaks.

Jean-Michel Cousteau invites you to embark on a breathtaking underwater voyage to discover the ultimate predator: the shark. Experience an astonishing up-close encounter in 3D with the Lions and Tigers of the Ocean. Come face-to-face with a multitude of shark species, including the Great White, Hammerhead, and Whale Shark. Witness them as they really are: not wicked man-eating creatures, but wild, fascinating and endangered animals that have been in existence a million years before dinosaurs roamed the Earth. Join a team of ocean explorers on a round-the-globe expedition documenting the life of the ultimate predator.