Travelling forward in time to 30,000 years ago, it's the middle of an ice age. The landscape is dominated by mighty mammoths, living side-by-side with woolly rhinos, giant deer and two separate species of human. The programme follows the fate of a herd of mammoths in their annual struggle against the harsh ice-age conditions. Every summer they spend on the grassy plains of what will one day become the bottom of the North Sea, but every winter they are forced to head for the less exposed valleys further south. It is a journey fraught with danger: mammoths can get trapped in frozen bogs, and the herd must run the gauntlet of hunters like cave lions and the deadly Neanderthals.

The power of visual storytelling is not a modern phenomenon, feature films today are using techniques developed way back in the distant past. For thousands of years, artists grappled with ways to bring their stories alive, to engage their audience. This is the story of how our ancient ancestors made the discoveries that have given films such a hold over our imaginations.

To fly like a bird, Earthflight not only captured remarkable images of wild flocks but also relied on some extraordinary relationships between people and birds. Filmed over four years, in six continents and more than 40 countries, the Earthflight team used many extraordinary techniques. For some of the unique flying shots, members of the team became part of the flock. The birds followed wherever they went - even in a microlight over Edinburgh and London. In Africa, paragliders floated alongside wild vultures, while a model vulture carried a camera inside the flock. In South America, wild-living macaws, that were rescued as babies, still come back to visit their 'foster mother' as he travels along a jungle river. In Africa, a radio-controlled 'drone' silently infiltrates masses of pink flamingos without disturbing a feather, and microlights and helicopters capture the dramatic moment white storks arrive over Istanbul. In Africa a tame vulture carried a camera across the African bush and recreated the behaviour of his wild relatives. Similarly, in the USA, a flock of hand-reared snow geese followed the migration route of wild flocks and took in the sights and sounds of New York - managing to get lost in Brooklyn

On the coast, two worlds collide. Coasts are the most dynamic and challenging habitats in the ocean - that brings great rewards but also great danger. The extraordinary animals that live here must find ingenious ways to cope with two very different worlds. This episode is a rollercoaster ride of heart-stopping action and epic drama, peopled with characters from the beautiful to the bizarre. We meet fish that live on dry land and puffins that must travel 60 miles or more for a single meal, and witness a life-and-death struggle in a technicolour rock pool. In a secluded cove in the Galapagos, sea lions feast on 60kg tuna. It should be impossible - tuna are usually far too fast for sea lions to catch. But here the sea lions club together to herd their prey inshore. Once trapped in the shallows, these huge fish are easy pickings. As the tide recedes in Brazil, lightfoot crabs leap from rock to rock, desperately avoiding the water - their lives depend on it. Moray eels launch themselves from rock pools, jaw gaping. Then octopuses, too. Both crawl across dry rock to set their ambush. Elsewhere, the ever-changing tides create rock pools. But these temporary worlds are a battleground. Predatory starfish turn a magical garden into the stuff of nightmares.

In the second episode, the directors learn their vision for the films is not always permissible by the U.S. government. Wyler is shocked by the racism he encounters against African American soldiers and refused to make a film recruiting black soldiers. Meanwhile, the films' racist depiction of the Japanese versus human depiction of the Germans causes worry for the War Department, which at that time planned to redistribute the Japanese-American population from internment camps into towns across the United States.

The five directors, John Ford, William Wyler, John Huston, Frank Capra, and George Stevens, return to Hollywood after the war but are forever haunted by what they saw. Ford goes on a drinking bender after filming the carnage at D-Day. Stevens is wholly unprepared for the horrors of Dachau and realizes he is not there to film propaganda but to capture evidence of crimes against humanity. Wyler, who lost his hearing during the war, fears his career is over. Huston chronicles soldiers suffering from postraumatic stress disorder in the film Let There Be Light, only to have it suppressed by the U.S. government.