- 1 Sudden Death
Documentary considering the nature of sudden death, the effects of coronary heart disease and the part they play.
Air Date: 1991-01-07
- 2 Keen as Mustard
This Horizon episode tells the story of the top secret experiments carried out to test the effects of mustard gas.
Air Date: 1991-01-14
- 3 Smokers Can Harm Your Health
Horizon investigates the case against passive smoking and reveals new evidence of its danger.
Air Date: 1991-01-21
- 4 Coming In from the Cold
Horizon reports on the new arms verification industry emerging due to the new arms control treaties.
Air Date: 1991-01-28
- 5 Small Problems with the Mirror
Horizon follows astronomer's efforts to rescue the Hubble space telescope and restore its original planned performance.
Air Date: 1991-02-04
- 6 Two Weeks to Save the Earth
Looks at the work of Earthwatch, and some of the many people who spend their holidays contributing to learning about the planet by helping on prehistoric digs, recording fish noises, tracking rodents, measuring grass an leaves and counting insects in places all over the world, often suffering much discomfort and boredom.
Air Date: 1991-02-10
- 7 California Dreaming
This Horizon documentary presents the US auto industry's response to clean-up the air in Los Angeles, California by the year 2007.
Air Date: 1991-02-11
- 8 The Day the Earth Melted
This episode of Horizon examines 20 years of research which has led to a new theory on how the earth's crust was made.
Air Date: 1991-02-25
- 9 The Curse of Karash
Looks at the phenomenon of the outbreaks of a lethal kidney disease amongst groups of people scattered around an area of the Balkans, covering Yugoslavia, Romania and Bulgaria, over the past 30 years.It considers the attempts and theories of scientists from all these countries over the years to find the cause of the disease.
Air Date: 1991-02-25
- 10 Playing at Noah
This Horizon interview presents Dr. Ulysses Seal who believes the "frozen zoo" concept is the best way to save vanishing species for the future generations.
Air Date: 1991-03-04
- 11 Cashing in on Paradise
This Horizon episode considers the pros and cons of "ecotourism" and the effects of tourism on the environment. The coral reefs of areas of Belize are suffering already from the effects tourists coming to the area. Rain forests and ape sanctuary areas employing the local community are also becoming a danger to the delicate environments.
Air Date: 1991-03-11
- 12 The Terracotta Time Machine
This episode of Horizon explores the Natural History Museum and its philosophy, both past and present. We look at some of the recent innovations that have been introduced in the past few years. The recent director of the museum, Dr. Neil Chalmers, justifies his policies, restructuring, and the academics. The scientists, who are adversely affected by the policies, air their own worries and concerns.
Air Date: 1991-03-18
- 13 Measuring the Roof of the World
Horizon examines the problems and cartography involved in mapping mountains such as Mount Everest. They follow the history of of mapping from those surveys conducted by mountaineering expeditions and early explorers, to modern mapping techniques using planes and satellites. Horizon also considers the startling news that K2 may actually be the world's tallest mountain according to recent satellite calculations.
Air Date: 1991-03-25
- 14 The First Americans
Horizon looks at archaeologist's new theories surrounding the population of the New World over 11,000 years ago
Air Date: 1991-04-15
- 15 Inside Chernobyl's Sarcophagus
Documentary following the clean-up operation at Chernobyl and the elite team of Soviet scientists working in areas of radiation that would be considered lethal in the West, whilst they hunt for missing fuel, uranium and plutonium, anxious that these could cause a second accident.
Air Date: 1991-04-22
- 16 Colonising Cyberspace
Horizon presents a documentary on how virtual reality can make humans feel as if they are present in the computer simulated artificial world. What is the future of all this powerful, seductive technology?
Air Date: 1991-04-29
- 17 Emerging Viruses
In this report, Horizon follows a group of eminent scientists who believe we have become too complacent about infectious diseases.
Air Date: 1991-05-13
- 18 Camelford - A Bitter Aftertaste
Horizon explores the Camelford disaster, in which aluminium sulphate was accidentally added to drinking water in Cornwall in 1988.
Air Date: 1991-05-20
- 19 Of Big Bangs, Stick Men and Galactic Holes
Several astronomers and scientists explore the concepts of "hot/cold dark space" and whether or not the "Big Bang" theory is actually correct, as well as considering the structures of galaxies.
Air Date: 1991-06-03
- 20 Food For Thought
This story by Horizon looks at the expanding and controversial area of "smart drugs".
Air Date: 1991-06-10
- 21 The Long Road to the West
In this Horizon episode, we look at the problems facing the Carl Zeiss optics company of Jena and other companies in the scientific sector of the former Eastern block countries. Following the reunification of Germany and the end of the Cold War, harsh economic conditions and the lack of scientific progress over the preceding decades in particular are explored.
Air Date: 1991-06-17
- 22 Half Hearted About Semi-Skimmed
Horizon examines the social and scientific issues around the cholesterol debate.
Air Date: 1991-06-24
- 23 T-Rex Exposed
Considers some of the different theories surrounding the Tyrannosaurus Rex dinosaur, and other members of the same family, and shows how calculations about size, speed, weight, etc. are made from skeletons, some of them recently discovered in Montana. Scientists also use the latest x-ray/scanning techniques to examine skulls and bones for information.
Air Date: 1991-07-01