Imagine if the food you eat could 'clean' your body and make you feel well. Dr Giles Yeo investigates the latest diet craze and social media sensation - clean eating. In a television first, Giles cooks with Ella Mills, the Instagram entrepreneur behind Deliciously Ella, one of the most popular brands associated with clean eating, and examines how far her plant-based cooking is based on science. She tells him clean has lost its way: "Clean now implies dirty and that's negative. I haven't used it, but as far as I understood it when I first read the term, it meant natural, kind of unprocessed, and now it doesn't mean that at all. It means diet, it means fad". Giles sifts through the claims of the Hemsley sisters, who advocate not just gluten-free but grain-free cooking, and Natasha Corrett, who popularises alkaline eating through her Honestly Healthy brand. In America, Giles reveals the key alternative health figures whose food philosophies are influencing the new gurus of clean. He discovers that when it comes to their promises about food and our health, all is not always what it appears to be. Inside a Californian ranch where cancer patients have been treated with alkaline food, Giles sees for himself what can happen when pseudoscience is taken to a shocking extreme.

The Horizon team have gathered together a team of scientists and doctors to investigate the incredible, natural material that is growing out of our heads - our hair. With access to the research laboratories of some of the world's leading hair care companies, including L'Oreal and ghd, the team explore the latest cutting-edge research and technology designed to push the boundaries of hair and hair care. Each one of us has a unique head of hair - an average of 150,000 individual hair strands growing approximately one centimetre every month. Over your lifetime, that is over 800 miles. The time and effort we put into styling, sculpting and maintaining this precious material has created a global hair care market worth a staggering £60 billion pounds. With such high stakes, it is inevitable that when developing hair-care products, science and business operate hand in hand. The team reveal how this industry science compares to the rigorous academic standards that they are used to. These investigations also reveal why we care so much about our hair, and whether or not it is worth splashing out on expensive shampoos. They uncover the magic ingredients found in conditioners and lay bare the secrets of the shiny, glossy hair seen in the adverts.

Comedian and impressionist Rory Bremner is on a personal mission to uncover the science of ADHD (attention deficit hyperactivity disorder), a condition which he has suspected he has. In this film, Rory learns about the science of ADHD, goes for a diagnosis and tries the drug methylphenidate (also known as Ritalin) for the first time - just before walking on stage.

Horizon follows three people living with voices, hallucinations and paranoia, to explore what causes this kind of phenomena. Providing a rare first-hand insight into these experiences, they reveal just what it is like to live with them day-to-day. They examine the impact of social, biological and environmental influences on conditions traditionally associated with insanity, such as schizophrenia and psychosis, and within the film they look at how new ways of understanding the brain are leading to a dramatic change in treatments and approaches and examine whether targeting the root causes of psychosis can lead to recovery. Above all, they try to uncover why it happened to them - and whether it could happen to you.

For decades some have suspected that there might be others out there, intelligent beings capable of communicating with us, even visiting our world. It might sound like science fiction, but today scientists from across the globe are scouring the universe for signals from extraterrestrials.

Horizon follows an international team of volcanologists in Iceland as they draw fascinating parallels with the volcanoes on Earth and those elsewhere in the solar system. Through the team's research, we discover that the largest volcano of the solar system - Olympus Mons on Mars - has been formed in a similar way to those of Iceland, how a small moon of Jupiter - Io - has the most violent eruptions anywhere, and find out that a moon of Saturn called Enceladus erupts icy geysers from a hidden ocean. Computer graphics combined with original NASA material reveal the spectacular sights of these amazing volcanoes. Along the way, we learn how volcanoes are not just a destructive force, but have been essential to the formation of atmospheres and even life. And through these volcanoes of the solar system, scientists have discovered far more about our own planet, Earth- hat it was like when Earth first formed, and even what will happen to our planet in the future.

Filmmaker Natalie Hewit follows the everyday people battling in the most extreme environment on Earth to move Halley VI, a vital polar research station. Britain's state-of-the-art Antarctic research base Halley VI is in trouble. Built on the Brunt Ice Shelf, it sits atop a massive slab of ice that extends far beyond the Antarctic shoreline. But the ice is breaking apart and just 6km from the station is a ginormous crevasse, which threatens to separate Halley from the rest of the continent, setting the £28 million base adrift on a massive iceberg. So Halley needs to move. But this is probably the toughest moving job on Earth, and the team of 90 who have been tasked with the mission aren't just architectural or engineering experts. They are plumbers, mechanics and farmers from across the UK and beyond - ordinary men and women on an extraordinary adventure. Their practical skills will be what makes or breaks this move.

A few weeks ago, the National Health Service was hit by a widespread and devastating cyber attack - Horizon tells the inside story of one of the most challenging days in the history of the NHS. On the morning of 12 May the attack started. Appointment systems, pathology labs, x-rays and even CT scanners were infected - putting not just data but patients lives at risk, and on every screen a simple - some may even say polite - message appeared. 'Ooops, your files have been encrypted!' But what followed was far from civilised. It was very clear that all the data on an infected machine was now scrambled and only the hackers could unscramble it. For a price - and with an extra twist - after a few days the ransom money doubled, and if nothing was paid within a week, the hackers threatened to destroy all the data - forever

This episode of Horizon looks at the issues that will change the way we live our lives in the future. Rather than relying on the minds of science fiction writers, mathematician Hannah Fry delves into the data we have today to provide an evidence-based vision of tomorrow. With the help of the BBC's science experts - and a few surprise guests - Hannah investigates the questions the British public want answered about the future.

The car has shrunk the world, increased personal freedom and in so many ways expanded our horizons, but there is a flipside. Fumes from car exhausts have helped to destroy our environment, poisoned the air we breathe and killed us in far more straightforward ways. But all that is going to change. This episode of Horizon enters a world where cars can drive themselves, a world where we are simply passengers, ferried about by wholesome green compassionate technology which will never ever go wrong. And it is almost here. Horizon explores the artificial intelligence required to replace human drivers for cars themselves, peers into the future driverless world and discovers that, despite the glossy driverless PR (and assuming that they really can be made to work reliably), the reality is that it might not be all good news. From the ethics of driverless car crashes to the impact on jobs, it might be that cars are about to rise up against us in ways that none of us are expecting.

Over the last two years, the BBC's science strand Horizon has been behind the scenes at London's Natural History Museum, following the dramatic replacement of the iconic Dippy the Dinosaur skeleton cast with the real skeleton of a blue whale - the world's biggest animal. Narrated by Sir David Attenborough, this special film follows the teams involved in what has to be one of the world's most unique engineering challenges. Replacing Dippy is brave and bold - it is the first thing visitors see when they enter the grand Hintze Hall, but the Natural History Museum is changing, and the installation of the colossal blue whale skeleton is the start of a new chapter. The largest animal ever to have lived, blue whales were driven to the brink of extinction by hunting and were the first species humans decided to save, telling an inspiring story of hope for the natural world.

Psychopaths have long captured the public imagination. Painted as charismatic, violent predators lacking in all empathy, they provide intrigue and horror in equal measure. But what precisely is a psychopath? What is it that drives them to cause harm, even kill? And can they ever be cured? Presented by psychologist Professor Uta Frith, this is an in-depth exploration of the psychopathic mind including one of the most notorious of all, Moors murderer Ian Brady. Through an ongoing correspondence between the Horizon team and Brady, the film features some of the very last letters he wrote. The film also features a series of candid interviews with prison inmates who not only describe their crimes but why they think they committed them. Horizon explores not only how each individual's crimes were shaped by their own life experiences, but also gives an insight in to how these people think and behave. Working with the world's experts in the field, the film sheds light on the biological, psychological and environmental influences that shape a psychopath. And it looks to the future, with groundbreaking research that suggests a lifetime of incarceration is not the only option to manage violent and dangerous psychopaths.

The dream of sending humans to Mars is closer than ever before. In fact, many scientists think that the first person to set foot on the Red Planet is alive today. But where should the first explorers visit when they get there? Horizon has gathered the world's leading experts on Mars and asked them where would they go, if they got the chance - and what would they need to survive? Using incredible real images and data, Horizon brings these Martian landmarks to life - from vast plains to towering volcanoes, from deep valleys to hidden underground caverns. This film also shows where to land, where to live and even where to hunt for traces of extra-terrestrial life. This is the ultimate traveller's guide to Mars.

A billion miles from home, running low on fuel, and almost out of time. After 13 years traversing the Saturn system, the spacecraft Cassini is plunging to a fiery death, becoming part of the very planet it has been exploring. As it embarks on its final assignment - a one-way trip into the heart of Saturn - Horizon celebrates the incredible achievements and discoveries of a mission that has changed the way we see the solar system. Strange new worlds with gigantic ice geysers, hidden underground oceans that could harbour life and a brand new moon coalescing in Saturn's magnificent rings. As the world says goodbye to the great explorer Cassini, Horizon will be there for with a ringside seat for its final moments.

How does a person know their gender? Do they see themselves as male or female, or somewhere in between? More and more people around the world do not identify with the gender they were assigned to at birth. Increasingly, people are expressing their gender identity outside of the 'norms', and the lines of gender are becoming more blurred than ever. This film explores what it actually means to be transgender, and what happens when a person transitions psychologically, physically and biologically. We follow a number of transgender people going through their own transition. From a socially transitioning transwoman to two young transmen embarking on hormones, to a transwoman going through gender confirmation surgery - we get a snapshot into what transitioning and being transgender is really like from those living it. We also hear from experts in the field of gender and find out how modern medicine is helping people to transition their gender. And we explore where gender identity actually comes from.