The episode begins in the South American rainforest whose rich variety of life forms is used to illustrate the sheer number of different species. Since many are dependent on others for food or means of reproduction, David Attenborough argues that they couldn't all have appeared at once. He sets out to discover which came first, and the reasons for such diversity. He starts by explaining the theories of Charles Darwin and the process of natural selection, using the giant tortoises of the Galapagos Islands (where Darwin voyaged on HMS Beagle) as an example. Fossils provide evidence of the earliest life, and Attenborough travels a vertical mile into the Grand Canyon in search of them.
Jungles provide the richest habitats on the planet - mysterious worlds of high drama where extraordinary animals attempt to survive in the most competitive place on earth. Flooded forests are home to caiman-hunting jaguars and strange dolphins that swim amongst the tree tops, while in the dense underworld, ninja frogs fight off wasps and flying dragons soar between trees. Acrobatic indri leap through the forests of Madagascar, while the jungle night conceals strange fungi and glow-in-the-dark creatures never filmed before.
With the help of some surprising creatures from around the world, this series sets out to discover how animals take to the air, defying the force all airborne animals must conquer, gravity. Part 2: Masters of the Sky This episode looks at powered flight, revealing why peregrine falcons can top 200 miles an hour, how a hummingbird is a slave to its own rather manic lifestyle and that the albatross's secret to flying for free is its nose. Heavyweight beetles break the rules to find love, a devious sparrow-hawk uses agility to execute a lightning-fast raid on his prey and half a million mother bats dominate the sky above, and below, the ground with a dazzling display of aerial prowess.
Huge changes have swept across Arabia since the discovery of oil and the Arab relationship with nature has changed too. This is summed up by the changes to camel racing, now an ultra hi-tech sport. Arabia's animals now live alongside a very modern society but Arabia's people are using technology to protect nature: dugongs are fitted with satellite transmitters; hunting falcons chase down radio-controlled planes and the world's first carbon-neutral city is being built in the very heart of oil country.
Across our planet, there are a handful of places that truly astonish, like Mount Everest, the Grand Canyon and Victoria Falls. These wonders seem to have little in common other than - literally - taking your breath away. But they share one other thing: they pose extraordinary challenges for their inhabitants. The second of two documentaries profiling some of the world's most expansive - and inhospitable - landscapes, and the people who live there. A fisherman in Zambia faces off against crocodiles and risks being swept to his death as he tries to make a living above the imposing Victoria Falls, and in the Amazon, a giant fish offers salvation to a hungry family that calls the river home. A boy's future hangs on the outcome of a single horse race in the vast grasslands of the Steppe, and in a European salt marsh, a young man duels with a savage bull in a centuries-old battle of wills.