Our strange rock itself can also be lethal. We tend to think of Earth as our life support but it's not there to support us at all. It's a place that's violent, that's beautiful, that's crazy, that's intense. Mother Nature is a serial killer. We wouldn't be here without mass suicide and events so devastating it makes the extinction of the dinosaurs looks like a tea party. There have been 5 mass extinctions on the planet and 99.9 percent of all species that have ever lived are gone.
Explore the story of how life on Earth has evolved, becoming lethal for life to thrive.

It all begins as a study on the psychology of prison life led by Stanford psychology professor Dr. Philip Zimbardo. 24 volunteers - 12 guards and 12 prisoners - have agreed to spend the next two weeks recreating life in a correctional facility. Normal people can become monsters, given the right situation, that's the standard narrative of the Stanford Prison Experiment, one of the most famous psychological experiments of all time.
But what if the cause of its participants' cruel behavior wasn't what we've always been told?

Where is everyone? We have been listening for messages from outer space for more than half a century, and so far... silence, why? Are we truly alone in the universe? Or is everyone else acting like us and just doing a lot of listening? Maybe we need to be louder. Maybe we need to send more messages out there. But how do you write a letter to an extraterrestrial whose language and culture and biology and mind we have no concept of? And what do you say?
Given all of the unknowns about what they might behave, should we say anything at all?

Today, worldwide, we each eat 27 pounds of chicken a year. Chicken's astonishing growth has been propelled and satisfied by a business that creates lives, and harvests them, at breathtaking speed and volume. But now the massive scale of production has exposed those in the chicken business to dangers large and small.
The ruthlessly efficient world of chicken production pits vulnerable growers against each other and leaves them open to vicious acts of sabotage.

The nervous system is fundamentally electric. When we move our arm, it moves because a electric signal has been sent to the muscle that controls it. Now, because the brain is electric, we could also use electricity to record what the brain is doing or bypass it entirely, and control a body. That means that we could restore movement to people who are paralyzed, feel through an artificial hand as if it was our own, and even read people's minds.
Michael Stevens explores how electricity can be used to move cockroaches, control other peoples' limbs and even read peoples' thoughts.

The second episode takes a look at how humans have always been voyagers and explorers, leaving the comfort of native shores to explore. Neil DeGrasse Tyson will show us a long-term vision of humanity's future worlds.