Seasons & episodes

Playful pets, fearsome fighters or deadly hunters? Millions of us have cats in our homes, yet we know very little about them. In this series, Liz Bonnin joins forces with some of the world's top cat experts to conduct a groundbreaking scientific study. With GPS trackers and cat cameras, we follow 100 cats in three very different environments to find out what they get up to when they leave the cat flap. In the first programme we discover how our cats see, hear and smell the world with the senses of their wild ancestors, and why this could be making life difficult for them in the modern world.

The second episode of this unique scientific study reveals the wild side of pet cats. Using GPS trackers and cat cameras, they show how these felines transform from pampered pet to purring predator as soon as they leave the cat flap. Liz Bonnin and some of the world's top cat experts put Ozzy and Smudge under surveillance to find out who is king of the street and reveal why, no matter how hard we try, we can't keep our cats' hunting instincts under control.

In the final episode of this groundbreaking scientific study, Liz Bonnin and a team of scientists reveal the secret language of our cats, the surprising conversations they have when we are asleep, and why they meow to us but not each other. We rig a house with cameras and cat trackers to discover if four cats living under one roof all get on as well as we would like to think. And we find out why living alongside us is making life difficult for our 21st-century cats.

Instead of reaching for the latest fad diet, the best way to lose weight successfully is a personalised approach - diets tailored to your individual biology and psychology. In a groundbreaking national experiment, Dr Chris van Tulleken and Professor Tanya Byron join a team of leading experts to put 75 overweight volunteers on diets designed to tackle the specific reasons why they eat too much. The volunteers are put through a series of tests at a residential clinic to understand how their genes, hormones and psychology influence their eating behaviour. They are then put on the diets the experts believe are best suited to them. Can science succeed where other diets have failed?

It is time to see if personalised dieting will work in normal life. The volunteers have been given one of three diets to follow - based on their genes, their hormones and their psychology. But now they are back at home, trying to stick to their personalised diets with all the stresses and temptations of real life. Dr Chris van Tulleken and Professor Tanya Byron discover how our genetic makeup can make temptation difficult to resist, how understanding the brain reveals what makes us comfort eat and what science can tell us about why we make disastrous food choices.

So far the volunteers have successfully been losing lost weight, but now the honeymoon period is over. It is the final two months of the diet, and their minds and bodies are fighting back. Dr Chris van Tulleken and Professor Tanya Byron find out if the new personalised diets will help them stay on course, and the experts reveal the scientific secrets to permanent dieting success.

Professor Brian Cox takes a journey through the BBC science archive to explore the story of mankind's relationship with the moon, from James Burke testing Nasa equipment to Neil Armstrong's first steps on the lunar surface and the dramatic tale of Apollo 13. He also asks whether international competition could help reignite the public's enthusiasm for space travel and bring about the dawn of a new space age.

In an intensely personal and often surprising film for BBC Two, Alastair Campbell candidly talks about his experience living with depression and explores if radical new treatments can make a difference. Alastair is best known for his role as Tony Blair’s formidable and often contentious spin doctor, but, away from the public eye, he has been dogged by crippling bouts of depression for most of his life. Some days, just getting out of bed is too hard. Therapy and anti-depressant medication is helping him keep his head above water, but is that really the best he can hope for? Encouraged by his family, Alastair sets out on a journey to explore if cutting edge science can offer him - and the millions of people like him - the hope of one day living depression-free. As he tries to understand his depression better, he also reflects on key events in his life and asks if they could have had a negative effect on his mind.

BBC weatherman Peter Gibbs makes an emotional return to Antarctica, years after he lived and worked at the British Antarctic Survey's Halley Research Station. (Part One as shown on BBC News)

BBC weatherman Peter Gibbs's return to Antarctica becomes something of a rescue mission. The British Antarctic Survey reveals how it will save the Halley Research Station from being cast adrift on an iceberg. (Part Two as shown on BBC News)

S0 · E125Coronavirus Special - Part 1 2020-04-09 · 60 min＋

Investigating the scientific facts and figures behind the biggest public health crisis in living memory as a new coronavirus takes an unprepared world by storm.

S0 · E126Coronavirus Special - Part 2 2020-05-19 · 60 min＋

Dr Chris van Tulleken, Dr Hannah Fry and Michael Mosley examine the latest research and explore some of the big questions about the new coronavirus and the pandemic it has created.

S0 · E127Coronavirus Special - What We Know Now 2021-02-25 · 60 min＋

In this third Horizon special, Dr Chris Van Tulleken is joined by his brother Xand and Dr Guddi Singh to take us through the latest developments and answer current concerns. Though the effect of the coronavirus pandemic has been devastating to many, the team reveal the breakthroughs in genetics, medicine and modelling that have provided a way out of this situation and given hope and confidence that, in the event of a future pandemic, we can take it on and win.

The extraordinary inside story of the biggest scientific challenge of our age - following a small band of vaccine scientists around the world who took on Covid-19 and ultimately delivered the weapon to beat it. As news of the coronavirus broke around the globe, a small group of scientists jumped into action to tackle one of the greatest medical challenges of our time: to create a vaccine against a virus no-one had ever seen before and to do so in record time, all during a deadly, global pandemic.

S0 · E129Tim Peake Special: How to Be an Astronaut 2015-12-13 · 59 min＋

In December 2015, Tim Peake became Britain’s first astronaut on board the International Space Station. For two years, he had been filming a video diary for Horizon as he prepared to leave. From family life to the rigorous training, this is an intimate portrait and remarkable insight into the world of an astronaut.

Horizon follows the work of R. Buckminster Fuller and his research of the geodesic dome.

Dr. Frank Darling and Dr. Eric Edson discuss different environmental priorities.

A reconstruction of a Michael Faraday lecture last given in December 1860.

S1 · E4Strangeness Minus Three 1964-07-25 · 60 min＋

Horizon explores the findings of physicists at Brookhaven, Long Island, New York. Who, after two years and thousands of photographs, have identified a predicted new particle which has a unique characteristic: 'strangeness minus three'.

Horizon looks at the work of the National Institute for Medical Research.

Prof. Arthur C. Clarke, Derek Price and Nigel Balchin discuss the past and future of science.

The work of amateur scientists.

Horizon investigates the 'Tots and Quots' and the 'Woodgeries' two groups set up by scientists before the second world war to discuss the future of science and how it effects society.

Horizon takes a look at science in the spirit of Christmas.