Horizon Season 21 Episode release dates & where to watch

1. The Intelligence Man

Sir Cyril Burt died in 1971, the most eminent psychologist of his age. Within two years the most bitter and disturbing scientific controversy since Piltdown Man saw Burt accused of lifelong faking and manipulation of phoney data. How and why was Burt allowed to get away with this?

2. Microworld!

Horizon looks at the research advances in physics and technology of microelectronics.

3. A New Green Revolution?

This episode of Horizon looks at the role of scientists in agriculture throughout the Third World countries.

4. Spies in the Wires

Horizon examines the various ways of committing computer fraud and at the efforts to prevent it and preserve our privacy.

5. Valley of the Inca

In this documentary, Horizon examines the work at an archaeological project in the Cusichaca Valley, Peru.

6. The Conquest of Parasites

Horizon presents this report on parasites, their life styles, and the diseases they cause in Third World countries.

7. Reflections on a River

Horizon investigates the life for various civilizations along the river Waveney in east Angola.

8. A Normal Face

Horizon presents a report on current research and trends in facial reconstructive surgery.

9. Prisoners of Incest

In this documentary, Horizon reconstructs a therapy session where a man imprisoned for incest meets his family for first time in two and one half years.

10. Signs of the Apes, Songs of the Whales

Horizon investigates the linguistic potential of non-human species.

11. Professor Bonner and the Slime Moulds

In the documentary, Horizon reports on the life of slime moulds and how they provides clues to cell differentiation.

12. The Mind of a Murderer: The Case of the Hillside Strangler

Horizon presents the first of a two-part documentary about Kenneth Bianchi, the Los Angeles Hillside Strangler, who was convicted of the murder of 12 women even though his defence was that he had no memory of the crimes.

13. The Mind of a Murderer: The Mask of Madness

Horizon presents the second part of a two-part documentary about Kenneth Bianchi, the Los Angeles Hillside Strangler, who was convicted of the murder of 12 women even though his defence was that he had no memory of the crimes.

14. A Cruel Inheritance

Horizon reports on new medical techniques to diagnose the inherited diseases; sickle cell anaemia and cystic fibrosis.

15. The Malvern Link

Horizon investigates the military bias of British scientific industries and the possible consequences if the bias continues.

16. Contented Cows and Other Animals

Horizon explores the behavioural patterns of sheep, cows, chickens, and pigs under both natural and intensive farming conditions.

17. Picking Winners

Horizon reports on the decline in the amount of gambling leading to a severe reductions in money to fund the scientific research in Britain.

18. The Brain Puzzle

Horizon documents the current medical research into finding new ways of repairing damage to the brain and the central nervous system.

19. Global Village

Horizon examines the concept and implications of a global village in Third World countries.

20. Ivan

In this documentary, Horizon spends a week with a victim of Parkinson's disease and how he has to use considerable muscular effort in order to cope with day-to-day life.

21. A Mathematical Mystery Tour

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

22. Supercharged Finale

Horizon presents a chronological history of the development of the racing car during the 15 years prior to World War II.