This week, we meet a girl whose heart has formed outside her ribcage, a man who can spend nine minutes underwater without taking a breath, a woman who is growing a second skeleton and a paralysed man who is regaining movement thanks to a chip implanted into his brain that can 'read' his brain signals.

In this episode, we take a look at the human body's amazing capacity for survival. We meet a man who injects himself with deadly snake venom, a woman who leads a normal life with only half a brain, a girl who collapses 50 times a day and the only man in the world to be completely cured of HIV.

This time, we meet a man who feels no pain, a woman who can smell Parkinson's disease, a man who can remember every face he has ever seen and a survivor of a head injury who woke up to find he could suddenly play the piano. These remarkable cases are shedding new light on one of the most mysterious parts of the human body - our brain.

This time, we meet a girl with two hearts, a man who can sing two notes at once, a woman who can bend in amazing ways, a girl who is allergic to everything and a man who can run 350 miles without stopping. These remarkable cases reveal the secret inner workings of our bodies - the ultimate piece of natural engineering.

Gabriel Weston continues to unlock the secrets of the human body, investigating some of the most extraordinary cases in medicine. First, she hears the story of a man with bones much stronger than the norm, and a girl whose arm will not stop growing. Dr Weston also learns of a woman who became pregnant with twins, but in two separate wombs, and a woman with a condition that means she is able to get lost within her own home.

Gabriel Weston continues to unlock the secrets of the human body, hearing the stories of a man who fixed his own heart and a girl whose immune system attacked her own brain. Dr Weston also hears the remarkable story of a man who can taste words, and how his condition is helping develop new ways for blind people to navigate and recognise colours. Last in the series.