Every year grizzly bear families in North America depend for their survival on a spectacular natural event: the return of hundreds of millions of salmon from the Pacific Ocean to the mountain streams where they were born. The salmon travel thousands of miles to spawn and then die. The great run not only provides food for bears, but for killer whales, wolves, bald eagles, and even the forest itself. The question is: will the salmon return in time to keep hungry bears alive?
A mother grizzly and her cubs emerge from their den high in snowy Alaskan mountains. Filming from the air the team capture a TV first, following the bears as they negotiate a near vertical slope on their journey to the coast where they await the return of the salmon. Meanwhile, the salmon are making their way to the to river mouths where they must swim upstream and against the current. The programme reveals how they tackle the torrents and leap over waterfalls, a feat equivalent to a human jumping over a house. Dozens of hungry bears eagerly await the salmon that make it up river. In another TV first, underwater cameras record the ingenuity and fancy footwork they use to collect dead salmon from the bottom of deep pools.

A mighty army of dolphins, sharks, whales, seals and gannets hunt down the billions of sardines along South Africa's east coast each winter. This is the Sardine Run: an underwater Armageddon, the greatest gathering of predators anywhere on the planet, and the most spectacular event in the world's oceans. From intimate moments of the creatures caught up in the run, to the dramatic finale of this spectacular event, The Great Tide is an action-packed feeding-frenzy, filmed underwater, on the ocean's surface, and in the air.
However, in recent years the sardine run has become less predictable, perhaps due to the warming effects of climate change. If the sardine run does not happen, the lives of the animals caught up in the drama hang in the balance. Pioneering a unique boat stabilised camera mount for surface filming, Nature's Great Events crew capture all the high octane action as the predators compete for sardines, filmed with aerial, underwater and above water cameras. Super slow motion cameras also capture the very moment gannets plunge into the water, hitting it at sixty miles an hour.
A violent winter storm is the trigger for the sardines to begin their desperate dash. They are followed by a super-pod of 5,000 dolphins and further up the coast more predators gather. A shoal of sardines 15 miles long is pushed into the shallows and aerial shots show thousands of sharks gathering to feed on them. The climax to the sardine run is a spectacular feeding frenzy as the dolphins round the sardines up into balls on which all the predators feast. Gannets rain down in their thousands, sharks pile in scattering the fish and a Bryde's whale lunges in taking great mouthfuls of sardines.

The end of a decade when the world was in crisis and inspiration and hope needed resurrecting, an influential duo released a masterpiece of popular music, Bridge Over Troubled Water. Through darkness and light, the album takes its listeners on an emotional ride echoing the era and one which continues to inspire an audience the world over 50 years later. Its symphonic hymn of a title track became an anthem for a generation.
The Harmony Game tells the story behind what is widely considered Simon and Garfunkel's best work, Bridge Over Troubled Water. The influential duo's last studio album has its legacy shrouded in rock n' roll mythology with legendary tales of inspiration, innovation and separation. Paul Simon, Art Garfunkel and their collaborators share the journey in their own words and reflect back on its impact 50 years later and includes never before seen film, photos and memorabilia.

The Indian Ocean is the third largest body of water on Earth at more than 6,000 miles wide and covering 13% of the world's surface. It is home to 5,000 species of fish, many of which only exist in the Indian Ocean. But it is also an ocean under threat from global issues such as over-fishing and climate change, which make this an ocean on the edge.

The tropical Indian Ocean is home to the Spice Islands. Characterised by beautiful sandy beaches, fringing coral reefs and coastal mangrove forests, this is a vibrant nursery area for marine life, such as whale sharks, crabs, seahorses and a great variety of fish. The coastal areas are where humans have the most direct impact on the ocean's resources.

The second programme deals with the mechanics of flight. Getting into the air is by far the most exhausting of a bird's activities, and Sir Attenborough observes shearwaters in Japan that have taken to climbing trees to give them a good jumping-off point. The albatross is so large that it can only launch itself after a run-up to create a flow of air over its wings. A combination of aerodynamics and upward air currents (or thermals), together with the act of flapping or gliding is what keeps a bird aloft. Landing requires less energy but a greater degree of skill, particularly for a big bird, such as a swan. Weight is kept to a minimum by having a beak made of keratin instead of bone, a light frame, and a coat of feathers, which is maintained fastidiously. The peregrine falcon holds the record for being fastest in the air, diving at speeds of over 300 km/h. Conversely, the barn owl owes its predatory success to flying slowly, while the kestrel spots its quarry by hovering. However, the true specialists in this regard are the hummingbirds, whose wings beat at the rate of 25 times a second. The habits of migratory birds are explored. After stocking up with food during the brief summer of the north, such species will set off on huge journeys southwards. Some, such as snow geese, travel continuously, using both the stars and the sun for navigation. They are contrasted with hawks and vultures, which glide overland on warm air, and therefore have to stop overnight.