Mathematician Dr Hannah Fry explores the mystery of maths. It underpins so much of our modern world that it's hard to imagine life without its technological advances, but where exactly does maths come from? Is it invented like a language or is it something discovered and part of the fabric of the universe? It's a question that some of the most eminent mathematical minds have been wrestling with. To investigate this question, Hannah goes head first down the fastest zip wire in the world to learn more about Newton's law of gravity, she paraglides to understand where the theory of maths and its practice application collide, and she travels to infinity and beyond to discover that some infinities are bigger than others.
In this episode, Hannah goes back to the time of the ancient Greeks to find out why they were so fascinated by the connection between beautiful music and maths. The patterns our ancestors found in music are all around us, from the way a sunflower stores its seeds to the number of petals in a flower. Even the shapes of some of the smallest structures in nature, such as viruses, seem to follow the rules of maths. All strong evidence for maths being discovered. But there are those who claim maths is all in our heads and something we invented. To find out if this is true, Hannah has her brain scanned. It turns out there is a place in all our brains where we do maths, but that doesn't prove its invented.
Experiments with infants, who have never had a maths lesson in their lives, suggests we all come hardwired to do maths. Far from being a creation of the human mind, this is evidence for maths being something we discover. Then along comes the invention of zero to help make counting more convenient and the creation of imaginary numbers, and the balance is tilted in the direction of maths being something we invented. The question of whether maths is invented or discovered just got a whole lot more difficult to answer

Mind reading might sound like pseudoscientific, but its scientific counterpart, thought identification, is very much a real thing. It's based in neuroimaging and machine learning, and what's really cool is that experiments in mind reading aren't just about spying on what someone is thinking. They're about figuring out what thoughts are even made of.
When you think of something, what does that mental picture actually look like? What resolution is it in? How high fidelity is a memory, and how do they change over time? In this episode, we are going to look at how reading people's minds can help us answer these questions.

Horizon uncovers the secret world of our dreams. In a series of cutting-edge experiments and personal stories, we go in search of the science behind this most enduring mystery and ask: where do dreams come from? Do they have meaning? And ultimately, why do we dream? What the film reveals is that much of what we thought we knew no longer stands true. Dreams are not simply wild imaginings but play a significant part in all our lives as they have an impact on our memories, the ability to learn, and our mental health. Most surprisingly, we find nightmares, too, are beneficial and may even explain the survival of our species.

The final episode of this series looks at what happens to the brain when someone uses psychedelic drugs. It looks at how psychedelic drugs may be useful in dealing with anxiety in cancer survivors and serious depression. It explores the history of psychedelics and examines early medical experimentation with the drug. It also discussed why psychedelics were banned and examines how they affect the brain.

In the dark depths of the oceans, nearly 90% of all species light up the darkness from within. These creatures flash, sparkle, shimmer, or simply glow. Whether it’s to scare off predators, fish for prey, or lure a mate, the language of light is everywhere in the ocean depths, and scientists are finally starting to decode it. Discover surprising ways to harness nature’s light—from tracking cancer cells to detecting pollution, lighting up cities, and even illuminating the inner workings of our brains.

The honey badger looks like something you might buy in pet shop and give to children, but turns out to be one of the most violent and determined creatures ever to scuttle across the face of the earth. Nothing in the badger’s world-not even the badgers themselves-are safe from its remarkable ability to create havoc and cause harm. Like a meter long skunk with the brain of a shark the Honey Badger’s metabolism compels it to eat constantly and live on the run. Its diet is admirably inclusive ranging from insects to its own young. If an animal is too big to eat then the badger will fight it anyway, indeed it is this almost supernatural tenacity that compels you respect it, as well as yielding some of the most spectacular sequences in the film. Five foot long cobra sleeping in the top of tree? No problem, the badger scoots up and bites its head off. When an ailing badger is attacked by a full size leopard it takes the leopard over an hour to finish it off. When one is bitten in the face by a snake that can kill a man, it just lies down for a while and sleeps it off.