What sort of alien civilizations might exist in the vastness of space? Terra is the fictional world imagined in Episode 4, a planet nine billion years old, twice as old as Earth. Old enough that a truly advanced intelligence could evolve. It was once a fertile world, now it is barren. But life can still thrive here in artificial domes. Over time, they've evolved not to need their bodies. They exist only as neural tissue. They never age, they never die. They're monitored and maintained by robots.
If alien civilizations are statistically so likely, why haven't astronomers found any sign of them? Where is everyone? Every time we look at an individual star, that's like dropping a bucket in the ocean. We're going to have to look at a lot of stars and to search through a lot of data until we find the clue that leads us to another civilization.

We sure lucked out with Planet Earth. Blue skies, rolling hills, water everywhere. But our home didn't come like this out of the box. Earth was a real fixer-upper, and it took some seriously hard work to build this paradise. Nearly four billion years of renovation. Some tiny, some huge, to make this house a home. Creatures on Earth don't just live and die. They actually change the world around them.
The story of how for nearly 4 billion years, microbes, plants and animals have emerged and sculpted the planet's surface and atmosphere in the strangest of ways.

Have planet hunters finally found proof of other Earth like worlds? Astronomers have now discovered over two hundred alien worlds, beyond our solar system, that were unknown just a decade ago. Discover planets that rage with fiery hurricanes and bizarre planets covered by water so dense that it forms a kind of hot ice. Among these weird worlds, Earth actually seems like the oddball.

The Arctic is the harshest environment on Earth: little food grows, it's dark for months on end, and temperatures stay well below freezing for much of the year. Yet four million people manage to survive here. Human Planet tells remarkable stories of extraordinary people who make their homes in nature's deep freeze. In springtime, Amos and Karl-Frederik set out across the sea ice with their dogs to catch a real-life sea monster: a Greenland shark! Inuit mussel-gatherers venture underneath the sea ice at low tide for a perilous race against time as they gather their food. And the children of Churchill, Manitoba, set out on the most dangerous trick or treating Halloween in the world: they risk coming face-to-face with deadly polar bears on the streets of their town. Who'll get the tastiest snack?

The Atlantic is the second largest ocean on the planet. It is the resting place of the Titanic, home to the mysterious Bermuda Triangle and is the youngest of the Earth's great oceans. It reaches depths of 8,500 metres. Oceans investigates this influential body of water from a group of islands in its western reaches - the Bahamas.

This documentary series charting the visual appeal and historical meaning of maps. The Hereford Mappa Mundi, the largest intact Medieval wall map in the world, its ambition to picture all of human knowledge in a single image is breathtaking. The work of a team of artists, the world it portrays is overflowing with life, featuring Classical and Biblical history, contemporary buildings and events, animals and plants from across the globe, and the infamous 'monstrous races' which were believed to inhabit the remotest corners of the Earth.