Most planets we know of are so hellish, it seems impossible that anything could live. But it's amazing where life can take hold in the Earth. Astrobiologists look for simple single-celled microbes known as extremophiles in places as Danakil Depression, known in Ethiopia as 'The Gateway to Hell.'
In Episode 2, the fictional world is Janus, a planet in such a close orbit than its rotation is locked by the star's gravity and it always shows the same face to its sun. On one side of the planet, it's always daytime, a searing desert. On the other side, it's forever night, a frozen shadowland. Squeezed between the two, a sliver of perpetual twilight. Freezing meltwater flows from the cold side, carving canyons through the landscape. Deep in these canyons lives an extraordinary five-legged creature.

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.

Global CO2 emissions coming from aviation will go from about 2% to, by 2050, something closer to 20%. Technology is the only key to open up a brighter future that can be sustainable at the same time. The way we fly is about to change, driven by a new breed of aviators not afraid to think differently. From clean, green electric aircraft to autonomous sky taxis, could the days of the jet age be numbered?

This look at the life, success and scandals of golf legend Tiger Woods shows original footage and revealing interviews, including his former caddy and close friend, Steve Williams; golf legend and six-time major champion Sir Nick Faldo; Earl Woods' friend and biographer, Pete McDaniel; Tiger's first true love, Dina Parr; as well as Rachel Uchitel, the woman at the center of the sex scandal that forever altered Tiger's world, breaking her silence for the first time.

Lesotho's Maseru Central Correctional Institute in Southern Africa holds the country's most dangerous and disturbed criminals. Shockingly almost half the inmates are doing time for rape. The culture of sexual violence in Lesotho has deep roots in society. Women are taken as secondary citizens in their culture. And sexual aggression continues inside the prison.
In this episode, Raphael Rowe will spend a week locked up in this African prison surrounded by sex offenders.

Albert Einstein, the most famous scientist of all time, was a world-renowned celebrity, greeted like a rock star when he appeared in public. An anti-war firebrand, Einstein also spoke out on issues ranging from women's rights and racism to immigration and nuclear arms control. But today, his image has been neutered into that of a charmingly absent-minded genius. He was, in fact, a powerful force for social change and a model for political activism.
Using a wealth of rarely-seen archival footage, correspondence, and new and illuminating interviews, filmmaker Julia Newman makes the case that Albert Einstein's example of social and political activism is as important today as are his brilliant, groundbreaking theories.