The true, stranger-than-fiction, adventure of eight visionaries who in 1991 spent two years quarantined inside of a self-engineered replica of Earth's ecosystem called Biosphere 2.
The experiment was a worldwide phenomenon, chronicling daily existence in the face of life threatening ecological disaster and a growing criticism that it was nothing more than a cult. The bizarre story is both a cautionary tale and a hopeful lesson of how a small group of dreamers can potentially re-imagine a new world.

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.

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 Sky at Night looks back at the last ten years of astronomy and ponders the most significant milestones and revelations. With the help of six distinguished astronomers, Chris and Maggie consider the state of astronomy in 2020 and wonder what new, exciting discoveries await us across the rest of the decade, as a host of new ground and space telescopes come online. Astronomer Royal Lord Martin Rees is among the guests to walk along the Astronomical Wall of Discovery in this one-hour special.

This series traces the history of classic video games, featuring insights from the innovators who brought these worlds and characters to life. In the first episode, Space Invaders and Pac-Man lead an arcade craze, while Atari's cartridge system dominates home gaming until high-profile failure sparks a downfall.

New technologies are making rockets cheaper and more powerful than ever before. As companies like SpaceX and Virgin Galactic make space more accessible, and NASA returns to crewed spaceflight, a new era of space exploration may be on the horizon.