Nature

The Blue Marble is an image of Earth taken on 1972, from a distance of about 18,000 miles from the planet's surface. It was taken by the crew of the Apollo 17 spacecraft on its way to the Moon. Before it was photographed from space, our perspective of Earth was fragmented and disconnected. Recent discoveries have revealed a dynamic and rapidly changing planet, above the crust and below.

Sunset over the plains of Kenya's Maasai Mara, one of Africa's most protected wild spaces. And home to the fastest land animal on Earth, the cheetah. These agile cats have always been thought of as daylight hunters. They target prey from more than a kilometre away and chase it down at over 100 kilometres an hour. In one of these plains, two cheetah brothers attempt a high-speed night hunt with a gang of powerful hyenas on their trail.

The Namib Desert is one of the oldest deserts and also one of the most diverse. With 50ºC (120ºF) temperatures and half a millimetre of rainfall annually, we see how this is possible. Half the size of Oklahoma, from its Skeleton Coast through the sea of sand to the haze of distant mountains this apparently forbidding desert hides secret water sources.

In Southeast Alaska, there's an ice-bound Eden that harbors possibly the richest temperate rainforests of all. Where the coastal mountains meet the Pacific, lays the Alexander Archipelago, a remote island chain running for almost 300 miles along the Alaskan Panhandle. This frozen frontier is one of the last great wildernesses of North America. And a stronghold for the country's highest diversity of megafauna, feasting on the abundance of fleeting summers to make it through relentless winters.

Plants that have developed to thrive in the desert, including cacti that grow in the shade of other trees and collect water in pleated trunks that expand and contract - but can also find themselves a host to other plants, like desert mistletoe. This programme also reveals how tobacco plants being eaten by caterpillars are able to summon the creatures' natural predators, and how tumbleweeds roll across the landscape, only unfurling and growing when they encounter rain.

Will Smith discovers hidden worlds of fast and slow in the Earth's oldest desert. Worlds where things go so fast or so slow we don't even know they're happening. This hidden world of speed is everywhere, even 80 feet underwater. Hundreds of tiny anemones, anchored to the rocks, but film them patiently, then speed it up, and this miniature world comes to life. A lizard's tongue is one of the fastest movements in the entire animal kingdom. An orca creates a shock wave by slapping her tail and that pulse can travel through the water at more than a thousand miles an hour. to stuns the herrings she hunts.