In this first episode Clark—travelling from Byzantine Ravenna to the Celtic Hebrides, from the Norway of the Vikings to Charlemagne's chapel at Aachen—tells the story of the Dark Ages, the six centuries following the collapse of the Roman Empire, and “how European thought and art were saved by 'the skin of our teeth'”. The thirteen programmes in the series outline the history of Western art, architecture and philosophy since the Dark Ages. The series was produced by the BBC and aired in 1969 on BBC2. Then, and in later transmissions in Britain, the US and other countries it reached an unprecedented number of viewers for an art series. Clark's book of the same title, based on the series, was published in 1969. Its production standards were generally praised and set the pattern for subsequent television documentary series. The New Yorker magazine described it as revelatory for the general viewer. The BBC's DVD issue in 2005 has remained in the catalogues, and the 1969 book has never gone out of print.

Carl Sagan teaches students in a classroom in his childhood home in Brooklyn, New York, which leads into a history of the different mythologies about stars and the gradual revelation of their true nature. In ancient Greece, some philosophers (Aristarchus of Samos, Thales of Miletus, Anaximander, Theodorus of Samos, Empedocles, Democritus) freely pursue scientific knowledge, while others (Plato, Aristotle, and the Pythagoreans) advocate slavery and epistemic secrecy. During the episode, Sagan correctly gives the students the prediction that astronomers will confirm the existence of exoplanets within their lifetime. Cosmos: A Personal Voyage is a thirteen-part television series written by Carl Sagan, Ann Druyan, and Steven Soter, with Sagan as presenter. It was executive-produced by Adrian Malone, produced by David Kennard, Geoffrey Haines-Stiles, and Gregory Andorfer, and directed by the producers, David Oyster, Richard Wells, Tom Weidlinger, and others. It covers a wide range of scientific subjects, including the origin of life and a perspective of our place in the universe. The series was first broadcast by the Public Broadcasting Service in 1980, and was the most widely watched series in the history of American public television until The Civil War (1990). As of 2009, it was still the most widely watched PBS series in the world. It won two Emmys and a Peabody Award, and has since been broadcast in more than 60 countries and seen by over 500 million people. As of 2018, the entire series is being broadcast on a permanent loop on Twitch. A book was also published to accompany the series. Cosmos: A Personal Voyage has been considered highly significant since its broadcast; David Itzkoff of The New York Times described it as "a watershed moment for science-themed television programming".