The BEST Episodes of Horizon

Every episode ever - ranked by fan votes!

Last Updated: Mar 26, 2021

Network: BBC Two

Horizon is BBC Two's flagship 50-minute science documentary series. In September 2014 it celebrated its 50th anniversary and it continues to enjoy outstanding critical acclaim. Recognised as the world leader in its field, it regularly wins a sweep of international science, medical and environmental film accolades, and has recently won the Royal Television Society Award and the Prix Italia. In 2002, the British Academy of Film & Television Arts presented Horizon with the BAFTA Television Award for Best Factual Series or Strand. In 2003 it won the prestigious Images et Science award for best medical documentary and the Carl von Linne Award at the Living Europe film festival in Sweden. That year, a Horizon co-production with WGBH Boston won the Emmy for best documentary.

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Prof. Regan's Supermarket Secrets

#1 - Prof. Regan's Supermarket Secrets

Season 2008 - Episode 7 - Aired Feb 26, 2008

Friendly bacteria, superfoods, cholesterol busting spreads, 99% germ free, whiter than'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?

star 10.00
28 votes
Inside Chernobyl's Sarcophagus (Update)

#2 - Inside Chernobyl's Sarcophagus (Update)

Season 1996 - Episode 10 - Aired Mar 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.

star 10.00
28 votes
The Secret You

#3 - The Secret You

Season 2009 - Episode 13 - Aired Oct 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.

star 10.00
28 votes
Molecules With Sunglasses

#4 - Molecules With Sunglasses

Season 1992 - Episode 3 - Aired Jan 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.

star 10.00
28 votes
Malaria: Battle of the Merozoites

#5 - Malaria: Battle of the Merozoites

Season 1992 - Episode 5 - Aired Feb 3, 1992

In this episode, Horizon look at attempts to persuade major respected organizations to do controlled trials on a synthetic malaria vaccine.

star 10.00
1 votes
Does the MMR Jab Cause Autism?

#6 - Does the MMR Jab Cause Autism?

Season 2005 - Episode 10 - Aired May 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.

star 9.87
30 votes
Tsunami: Naming the Dead

#7 - Tsunami: Naming the Dead

Season 2005 - Episode 12 - Aired Sep 1, 2005

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

star 9.83
30 votes
Smoker's Luck

#8 - Smoker's Luck

Season 1980 - Episode 20 - Aired Nov 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.

star 9.83
30 votes
The Pleasure Of Finding Things Out

#9 - The Pleasure Of Finding Things Out

Season 1981 - Episode 24 - Aired Nov 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.

star 9.82
33 votes
The Blind Watchmaker

#10 - The Blind Watchmaker

Season 1987 - Episode 3 - Aired Jan 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.

star 9.78
32 votes
Directors: Sean Smith
Homeopathy: The Test

#11 - Homeopathy: The Test

Season 2002 - Episode 16 - Aired Nov 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.

star 9.74
31 votes
New Star in Orbit

#12 - New Star in Orbit

Season 1999 - Episode 6 - Aired Mar 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.

star 9.72
32 votes
Einstein's Unfinished Symphony

#13 - Einstein's Unfinished Symphony

Season 2005 - Episode 2 - Aired Jan 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.

star 9.46
59 votes
What is Reality?

#14 - What is Reality?

Season 2011 - Episode 2 - Aired Jan 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.

star 9.05
243 votes
Do You Know What Time It Is?

#15 - Do You Know What Time It Is?

Season 2008 - Episode 15 - Aired Dec 2, 2008

Particle physicist Professor Brian Cox asks, 'What time is it?' It's a simple question and it sounds like it has a simple answer. But do we really know what it is that we're asking? Brian visits the ancient Mayan pyramids in Mexico where the Maya built temples to time. He finds out that a day is never 24 hours and meets Earth's very own Director of Time. He journeys to the beginning of time, and goes beyond within the realms of string theory, and explores the very limit of time. He discovers that we not only travel through time at the speed of light, but the experience we feel as the passing of time could be an illusion.

star 9.00
38 votes
Now the Chips Are Down

#16 - Now the Chips Are Down

Season 1978 - Episode 9 - Aired Mar 31, 1978

About the applications and implications for the future, particularly the effects on the labour market, of microprocessors.

star 9.00
31 votes
Einstein's Equation of Life and Death

#17 - Einstein's Equation of Life and Death

Season 2005 - Episode 3 - Aired Jan 27, 2005

The story of Einstein's most famous equation E=mc² – its role in the creation of the atom bomb and our understanding of the beginnings of the Universe. 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.

star 9.00
28 votes
Malaria: Defeating the Curse

#18 - Malaria: Defeating the Curse

Season 2005 - Episode 11 - Aired Jun 5, 2005

This is the story by Horizon of an epic battle between science and nature. It's a battle to destroy a disease that is one of the biggest killers on the planet: malaria.

star 9.00
28 votes
How Violent Are You?

#19 - How Violent Are You?

Season 2009 - Episode 11 - Aired May 12, 2009

What makes ordinary people commit extreme acts of violence? Michael Portillo investigates the dark side of human nature, and discovers what it is like to inflict pain.

star 9.00
28 votes
Dr Money and the Boy with No Penis

#20 - Dr Money and the Boy with No Penis

Season 2004 - Episode 18 - Aired Nov 4, 2004

On 22 August 1965 Janet Reimer was granted her dearest wish: she gave birth to twins. The two boys, Brian and Bruce, were healthy babies, but they would lead tragic lives, blighted by one scientist's radical theory. When they were seven months old, the boys, who lived in Winnipeg, Canada, were sent to the local hospital for a routine circumcision. Unfortunately the doctor in charge of the procedure was using electrical equipment, which malfunctioned several times. On the last trial, Bruce's entire penis was burnt off. Brian was not operated on. The family were distraught. In the Sixties plastic surgery was not an option: even today it is not recommended that new-borns undergo penis reconstruction operations. It wasn't until several months later that Janet and her husband, Ron, saw a television programme that gave them some hope. Dr John Money, a highly renowned sexologist, featured in a debate about sex change operations on transsexuals. He had brought a transsexual with him who was convincingly feminine looking. Perhaps, thought Janet Reimer, this was the solution - they could turn their baby son into a daughter. She wrote to Dr Money immediately. He responded swiftly and invited them to come and visit him in Baltimore, Maryland. Dr Money is a highly intelligent, well respected, charismatic individual. He suggested to the Reimers that they bring their son up as a girl. Thus, when Bruce was 18 months old, he was castrated and a rudimentary vulva was created for him. The family now called him Brenda and tried to treat him like a little girl. Dr Money was the answer to the Reimers' prayers, but they were the answer to his too. He had studied people known then as hermaphrodites, now referred to as intersex, who are physically both male and female. As it was surgically easier to turn these people into females, this was standard practice. Dr Money had used case studies of hermaphrodites to show that there was a window of opportunity for surgery - a 'gen

star 9.00
28 votes
Noah's Flood

#21 - Noah's Flood

Season 1996 - Episode 16 - Aired Dec 16, 1996

Follows the work of geologists Bill Ryan and Walter Pitman, who for twenty five years have been investigating evidence for the location of the biblical flood and Noah's Ark.

star 9.00
28 votes
The Runaway Mountain

#22 - The Runaway Mountain

Season 1995 - Episode 20 - Aired Dec 11, 1995

Horizon presents the story of the search for an explanation of how rock can flow like water.

star 9.00
1 votes
Before Babel

#23 - Before Babel

Season 1992 - Episode 12 - Aired Apr 6, 1992

Horizon explores the development of languages all over the world and attempts to reconstruct the first spoken words.

star 9.00
1 votes
No Ordinary Genius (1)

#24 - No Ordinary Genius (1)

Season 1993 - Episode 4 - Aired Jan 25, 1993

This is the first part of a two-part Horizon series presenting a portrait of Richard Feynman, the American Nobel Prize winning physicist.

star 9.00
3 votes
Cannabis: Miracle Medicine or Dangerous Drug?

#25 - Cannabis: Miracle Medicine or Dangerous Drug?

Season 2019 - Episode 6 - Aired Aug 28, 2019

At a pivotal moment in the history of one of the world’s oldest drugs, Dr Javid Abdelmoneim investigates the latest medical and scientific research into the effects of cannabis on the brain and body.

star 9.00
5 votes