The BEST episodes of Horizon

Every episode of Horizon ever, ranked from best to worst by thousands of votes from fans of the show. The best episodes of Horizon!

Amazing science stories, unravels mysteries and reveals worlds you've never seen before.

Last Updated: 3/11/2024Network: BBC TwoStatus: Continuing
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Prof. Regan's Supermarket Secrets
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10.00
28 votes

#1 - Prof. Regan's Supermarket Secrets

Season 2008 - Episode 7 - Aired 2/26/2008

Friendly bacteria, superfoods, cholesterol busting spreads, 99% germ free, whiter than white...it's almost impossible to find a product in the supermarket today that doesn't come with impressive claims...a scientific claims, but do they actually do what they say? Are they worth the price? Are they worth a place in Prof. Regan's shopping trolly?

New Star in Orbit
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10.00
28 votes

#2 - New Star in Orbit

Season 1999 - Episode 6 - Aired 3/11/1999

In this report, Horizon explores the arguments for and against the building of the Space Station Freedom and will it ever justify it's huge cost.

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Inside Chernobyl's Sarcophagus (Update)
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10.00
28 votes

#3 - Inside Chernobyl's Sarcophagus (Update)

Season 1996 - Episode 10 - Aired 3/25/1996

In this episode of Horizon, which is a follow-up to the 1991 documentary, we follow a group of soviet scientists on a suicide mission as they search for the missing nuclear fuel inside the remains of the nuclear reactor 4.

The Blind Watchmaker
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10.00
28 votes

#4 - The Blind Watchmaker

Season 1987 - Episode 3 - Aired 1/19/1987

In this interview by Horizon, zoologist Richard Dawkins investigates an attack on evolution by scientific creationists, based on the book of the same name by the famous zoologist.

Directors: Sean Smith
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The Pleasure Of Finding Things Out
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10.00
28 votes

#5 - The Pleasure Of Finding Things Out

Season 1981 - Episode 24 - Aired 11/23/1981

Richard Feymann was one of the most brilliant theoretical physicists and original thinkers or the 20th century. He rebuilt the theory of quantum electrodynamics, and it was for this work that he won the Nobel Prize in 1965. In this documentary he talks about his motivations to be a scientist and a teacher of science.

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Smoker's Luck
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10.00
28 votes

#6 - Smoker's Luck

Season 1980 - Episode 20 - Aired 11/3/1980

Documentary about smoking and about the secondary effects of it. Britain leads the world in smoking deaths at 200 per day. The film looks at prognosis of deat h and at the chances of those who give up smoking of dying of the effects.

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The Secret You
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10.00
28 votes

#7 - The Secret You

Season 2009 - Episode 13 - Aired 10/20/2009

With the help of a hammer-wielding scientist, Jennifer Aniston and a general anaesthetic, Professor Marcus du Sautoy goes in search of answers to one of science's greatest mysteries: how do we know who we are? While the thoughts that make us feel as though we know ourselves are easy to experience, they are notoriously difficult to explain. So, in order to find out where they come from, Marcus subjects himself to a series of probing experiments. He learns at what age our self-awareness emerges and whether other species share this trait. Next, he has his mind scrambled by a cutting-edge experiment in anaesthesia. Having survived that ordeal, Marcus is given an out-of-body experience in a bid to locate his true self. And in Hollywood, he learns how celebrities are helping scientists understand the microscopic activities of our brain. Finally, he takes part in a mind-reading experiment that both helps explain and radically alters his understanding of who he is.

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Molecules With Sunglasses
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28 votes

#8 - Molecules With Sunglasses

Season 1992 - Episode 3 - Aired 1/20/1992

About the original discovery in 1985 of a third form of solid carbon, named Buckminsterfullerene after the architect who invented geodesic domes. The two scientists who discovered the material glimpsed it for brief seconds only in their lasers but neither they nor other scientists subsequently could make the substance last long enough in the laser to prove their theory. Then in 1990, a couple of physicists with an arc-welder in a bell-jar found they could make as much Buckminsterfullerene as they liked, and industrial applications opened up, with talk of new polymers, molecular ball-bearings, lubricants and super- conductors. Meanwhile, the original discoverers were turning back to the fundamental questions surrounding the discovery, such as how and why does it form; does it exist in space or is it the solution to one of the great mysteries of the universe.

Is Your Brain Male or Female?
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10.00
28 votes

#9 - Is Your Brain Male or Female?

Season 2014 - Episode 15 - Aired 9/29/2014

Dr Michael Mosley and Professor Alice Roberts investigate if male and female brains really are wired differently. New research suggests that the connections in men and women's brains follow different patterns, patterns which may explain typical forms of male and female behaviour. But are these patterns innate, or are they shaped by the world around us? Using a team of human lab rats and a troop of barbary monkeys, Michael and Alice test the science and challenge old stereotypes. They ask whether this new scientific research will benefit both men and women - or whether it could drive the sexes even further apart.

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Tsunami: Naming the Dead
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10.00
28 votes

#10 - Tsunami: Naming the Dead

Season 2005 - Episode 12 - Aired 9/1/2005

How the biggest international forensic operation in history identified the victims of the most devastating natural disaster of recent times.

Does the MMR Jab Cause Autism?
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9.87
30 votes

#11 - Does the MMR Jab Cause Autism?

Season 2005 - Episode 10 - Aired 5/29/2005

In this documentary, Horizon presents the largest public health issue of recent years that has attracted such heated debate as the question of whether the MMR vaccine can cause autism. The MMR jab combines three childhood vaccines, against measles, mumps and rubella, into one injection, which is first given to children at around 12-18 months. Horizon presents new, exclusive evidence about the MMR jab.

Homeopathy: The Test
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9.74
31 votes

#12 - Homeopathy: The Test

Season 2002 - Episode 16 - Aired 11/26/2002

Homoeopathy was pioneered over 200 years ago. Practitioners and patients are convinced it has the power to heal. Today, some of the most famous and influential people in the world, including pop stars, politicians, footballers and even Prince Charles, all use homoeopathic remedies. Yet according to traditional science, they are wasting their money. Sceptic James Randi is so convinced that homoeopathy will not work, that he has offered $1m to anyone who can provide convincing evidence of its effects. For the first time in the programme's history, Horizon conducts its own scientific experiment, to try and win his money. If they succeed, they will not only be $1m richer - they will also force scientists to rethink some of their fundamental beliefs. The basic principle of homoeopathy is that like cures like: that an ailment can be cured by small quantities of substances which produce the same symptoms. For example, it is believed that onions, which produce streaming, itchy eyes, can be used to relieve the symptoms of hay fever.

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Strange Signals from Outer Space!
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9.50
56 votes

#13 - Strange Signals from Outer Space!

Season 2017 - Episode 5 - Aired 5/16/2017

Horizon investigates claims of signals from extra terrestrials. In 2006, Duncan Lorimer and Maura McLaughlin discovered a enigmatic signal from space, known as a fast radio burst. It was a pulse of radiation so bright, it didn't appear to be caused by any known object in the universe. Explanations ranged from colliding neutron stars to communication signals from an alien civilisation. Scientists have been searching the cosmos for strange signals like the 'Lorimer Burst' for more than 50 years, ever since astronomer Frank Drake convened a secretive meeting of a group of scientists calling themselves the 'Order of the Dolphin'. The film ends with scientists latest search for extra-terrestial intelligence - Horizon obtained exclusive access to film researchers at the Green Bank Telescope searching for radio signals from 'Tabby's Star' - a star so mysterious some scientists believe might be surrounded by a Dyson Sphere - a vast energy collector built by advanced aliens.

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Einstein's Unfinished Symphony
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9.46
59 votes

#14 - Einstein's Unfinished Symphony

Season 2005 - Episode 2 - Aired 1/20/2005

The unpredictable results of the Theory of Relativity. Horizon brings you the second part of a two-part series on Albert Einsten. In the summer of 1939 Albert Einstein was on holiday in a small resort town on the tip of Long Island. His peaceful summer, however, was about to be shattered by a visit from an old friend and colleague from his years in Berlin. The visitor was the physicist Leo Szilard. He had come to tell Einstein that he feared the Nazis could soon be in possession of a terrible new weapon and that something had to be done.

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How Big Is the Universe?
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9.20
140 votes

#15 - How Big Is the Universe?

Season 2012 - Episode 12 - Aired 8/27/2012

Cosmologists talk about their project to create a map of everything in existence, and also reveal that their research has some highly unexpected results, creating a picture stranger than anything they had ever imagined.

Directors: Kenny Scott
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What is Reality?
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9.10
224 votes

#16 - What is Reality?

Season 2011 - Episode 2 - Aired 1/17/2011

There is a strange and mysterious world that surrounds us, a world largely hidden from our senses. The quest to explain the true nature of reality is one of the great scientific detective stories. Clues have been pieced together from deep within the atom, from the event horizon of black holes, and from the far reaches of the cosmos. It may be that that we are part of a cosmic hologram, projected from the edge of the universe. Or that we exist in an infinity of parallel worlds. Your reality may never look quite the same again.

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A Mathematical Mystery Tour
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9.00
28 votes

#17 - A Mathematical Mystery Tour

Season 1984 - Episode 21 - Aired 12/10/1984

Horizon attempts to explain some of the theories proposed by pure mathematicians over the ages.

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Volcanoes of the Solar System
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9.00
28 votes

#18 - Volcanoes of the Solar System

Season 2017 - Episode 6 - Aired 5/23/2017

Volcanoes have long helped shape the Earth. But what is less well known is that there are volcanoes on other planets and moons that are even more extraordinary than those on our own home planet. Horizon follows an international team of volcanologists in Iceland as they draw fascinating parallels between the volcanoes on Earth and those elsewhere in the solar system. Through the team's research, we discover that the largest volcano in 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 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.

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Clean Eating: The Dirty Truth
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9.00
28 votes

#19 - Clean Eating: The Dirty Truth

Season 2017 - Episode 1 - Aired 1/19/2017

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.

Directors: Tristan Quinn
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Curing Alzheimer's
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9.00
56 votes

#20 - Curing Alzheimer's

Season 2016 - Episode 9 - Aired 5/11/2016

Horizon investigates a new era of Alzheimer's research, which is bringing hope to millions of sufferers across the world. New scanning and gene technology is allowing scientists to identify the disease at its earliest stages, often 15 years before symptoms appear and the brain cells are destroyed. A series of new drugs trials in Colombia, the USA and Europe are showing startling success in reducing beta amyloid, the protein which is a hallmark of the disease. It is also becoming clear that changes in lifestyle can prevent the development of the disease. A new system inside the brain has been discovered which clears amyloid when we are in deep sleep, but allows it to accumulate if we don't sleep well. The programme reveals that for sufferers in the early stages of the disease, brain connections, or synapses, can be strengthened and even replaced by absorbing enough of the right nutrients. A UK-wide trail helps sufferers in the early stages to concentrate on improving everyday tasks, and in the process not only make their lives easier, but helps to reactivate the planning and organisational parts of the brain. In an ageing world, where the biggest risk of developing Alzheimer's is old age, the scientific breakthroughs in Alzheimer's disease are bringing hope where once there was despair.

Directors: Charles Colville
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The End of the Solar System
star
9.00
56 votes

#21 - The End of the Solar System

Season 2016 - Episode 5 - Aired 4/13/2016

This is the story of how our solar system will be transformed by the aging sun before coming to a spectacular end in about eight billion years. Astronomers can peer into the far future to predict how it will happen by analysing distant galaxies, stars and even planets in their final moments. In this film, Horizon brings these predictions to life in a peaceful midwestern town that has a giant scale model of the solar system spread out all over the city. As it ages, the sun will bloat into a red giant star, swallowing planets... as well as half the town. The fate of the Earth itself hangs in the balance. How will the solar system end?

Directors: George Harris
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Cosmic Dawn: The Real Moment of Creation
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9.00
28 votes

#22 - Cosmic Dawn: The Real Moment of Creation

Season 2015 - Episode 11 - Aired 9/9/2015

Forget the big bang. The real moment of creation was the Cosmic Dawn - the moment of first light. This is the scientific version of the story of Genesis. The big bang gets all the credit for creating our universe. But in fact, the universe it gave was dark and boring. There were no stars, no galaxies, just a vast, black fog of gas - the cosmic dark ages. But, after a hundred million years of nothing, came a dramatic moment of transformation - the Cosmic Dawn. It's the moment the first stars were born, the moment that lit up the Universe, and made the first structure and the first ingredients of life. This was the real moment of creation. Astronomers are now trying to witness the cosmic dawn. For the first time they have the tools to explore the very first stars of the universe and to tell the scientific story of our creation.

Directors: Toby MacDonald
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Which Universe Are We In?
star
9.00
28 votes

#23 - Which Universe Are We In?

Season 2015 - Episode 10 - Aired 9/2/2015

Imagine a world where dinosaurs still walk the earth. A world where the Germans won World War II and you are President of the United States. Imagine a world where the laws of physics no longer apply and where infinite copies of you are playing out every storyline of your life. It sounds like a plot stolen straight from Hollywood, but far from it. This is the multiverse Until very recently the whole idea of the multiverse was dismissed as a fantasy, but now this strangest of ideas is at the cutting edge of science.And for a growing number of scientists, the multiverse is the only way we will ever truly make sense of the world we are in. Horizon asks the question: Do multiple universes exist? And if so, which one are we actually in?

Directors: Naomi Austin
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First Britons
star
9.00
28 votes

#24 - First Britons

Season 2015 - Episode 8 - Aired 8/19/2015

Horizon reveals how new archaeological discoveries are painting a different picture of the very first native Britons. For centuries it's been thought that these hunter-gatherers lived a brutal, hand-to-mouth existence. But extraordinary new evidence has forced scientists to rethink who these people were, where they came from and what impact they had on our early history. Now, our impression is of a hardy, sophisticated people who withstood centuries of extreme climate change and a devastating tsunami that was to give birth to the island nation of Britain. Their way of life may even have survived beyond its greatest ever threat - the farming revolution.

Directors: Penny Palmer
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What Makes us Human?
star
9.00
28 votes

#25 - What Makes us Human?

Season 2013 - Episode 9 - Aired 7/3/2013

Professor Alice Roberts is making a new human being - she is pregnant with her second child. But before he is born, she wants to find out what makes a human, human? What is that separates us from our closest living relatives - the chimpanzees? We share 99% of our DNA with chimpanzees and yet from the moment of birth, our lives are completely different. So are we just another animal, or is there something special about being human? Before her new baby emerges into the world, Professor Roberts sets out to explore what it is about our bodies, our genes and ultimately our brains that set us apart from our furry cousins - what is it that truly makes us human?

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