Season 9 · Episode 21 — Sex Can Be a Problem

In this episode of Horizon, you find out how feasible it is to build a 35 mile long tunnel between Britain and France.

Horizon explores the American Navajo indian tribe of New Mexico, in the United States.

Why do humans have such a poor sense of smell as compared to animals? Horizon investigates why.

This story by Horizon reports on Malaria in the country of Gambia, in West Africa.

Horizon investigates reports of strange phenomena and about what the scientific theory is about these phenomena.

Horizon explores if a doctor's treatment of the patient is always in the best interest of the patient.

In this episode, Horizon looks the the ecological movement, and the resistance against the movement in Britain, and the USA.

In this report by Horizon, the effect of boring jobs on industrial relations is looked at, along with work and job satisfaction.

Horizon looks at the life of whales and dolphins, and how they interact with man.

Horizon investigates the various conceptions of "race" that have arisen since the 17th century.

Horizon investigates the use of hydroelectric power in Africa, at Lake Kariba, Lake Volta, and Lake Nasser.

This episode of Horizon follows the expedition of two German naturalists exploring the Northwestern desert of the Sahara in Africa.

This story by Horizon is about American research into techniques for controlling bodily functions with the mind.

In this report, Horizon looks at the various aspects of volcanoes and explaining the views of some vulcanologists.

Horizon presents a study of Thomas Alva Edison and his achievements as an inventor.

Horizon reviews the history of train accidents and the new safety precautions to prevent them.

Horizon investigates the threat to the Snowdonia National Park in Britain, from mining companies.

Horizon reports on modern research in the prevention of tooth decay.

How do muscles contract and how are they are controlled from the brain through nerve fibers are the subjects of this Horizon episode.

This episode of Horizon explores bacteria and other creatures that live on our skin and in our hair.

Horizon explores the development and techniques of brain surgery from the 1950's to present-day in Britain and the USA.

Horizon reconstructs a day in the life of the old Charing Cross Hospital in Britain just fifty years ago.

This episode of Horizon looks the how the ice age physically shaped the British landscape.

This episode of Horizon illustrates the ideas of Prof. W.G. Hoskins on the development of the English landscape from Iron Age times to the…

Horizon reports that High Energy Physics shows a pattern of thought that challenges the very roots of commonplace belief.

This episode of Horizon is about the east coast marshes of America, called the "Wetlands" and the effects of urban development on the wildl…

Horizon investigates the research that is going into the ageing process to find out its causes and possible prevention.

This epidsode of Horizon reports on how a group of zoologists at Oxford Scientific Films in England makes films.

Horizon documents fire prevention, and fire fighting.

This episode of Horizon centers on the exploitation of oil in Alaska, and the effects of it on the Eskimoes and the local wildlife.

Horizon reports on people suffering from kidney diseases and the current forms of treatment.

Horizon documents how in Europe, they are using water canals for industrial transport, as an alternative to roads.