The episode, devoted to the planet Mars, begins with scientific and fictional speculation about the Red Planet during the late nineteenth and early twentieth centuries (H. G. Wells' The War of the Worlds, Edgar Rice Burroughs' science fiction books, and Percival Lowell's false vision of canals on Mars). It then moves to Robert Goddard's early experiments in rocket-building, inspired by reading science fiction, and the work by Mars probes, including the Viking, searching for life on Mars. The episode ends with the possibility of the terraforming and colonization of Mars and a Cosmos Update on the relevance of Mars' environment to Earth's and the possibility of a manned mission to Mars.

'It's alive!' Since Dr. Frankenstein spoke those famous words, we've been alternately enthralled and terrified by the idea of creating life in the lab. Now, a revolution in genetic engineering and thrilling innovations in synthetic biology are bringing that dream—or nightmare, as the case may be—closer to reality. New tools allow researchers to use cells to create their own DNA and edit it into existing genomes with more ease and less cost than ever before.
Along with renewed hopes for treating some genetic diseases, there's serious talk of using the newest technologies to bring long-extinct animals back from the dead – like the team hoping to resurrect the woolly mammoth. Science fiction is quickly becoming science fact. Another daring genetic experiment to bioengineer animals could prevent Lyme disease. But the power to make life comes with deep ethical questions. What are the potential rewards—and dangers—of tinkering with nature? This films explores the benefits and the burden of risk surrounding the controversial new technology.

Space colonization is no longer the fodder of science fiction, it is becoming a reality. Examine the efforts underway to establish a human colony on Mars, including how they plan to grow food, recycle wastewater and introduce greenhouse gases to revive the red planet and make it more habitable for humans. Cutting-edge computer graphics are used to bring the universe down to earth to show what life would be like on Mars, and to imagine what kind of life forms might evolve in alien atmospheres.

Science fiction has long anticipated the rise of machine intelligence. Today, a new generation of self-learning computers is reshaping every aspect of our lives. Incomprehensible amounts of data are being collected, interpreted, and fed back to us in a tsunami of apps, smart devices, and targeted advertisements.
Virtually every industry on earth is feeling this transformation, from job automation to medical diagnostics, from elections to battlefield weapons. Do You Trust This Computer? explores the promises and perils of this developing era. Will A.I. usher in an age of unprecedented potential, or prove to be our final invention?

Time travel is not forbidden by the laws of nature, but to build a time machine, we would need to understand more about those laws and how to subvert them than we do now. And every day, science does learn more. In this film Horizon meets the scientists working on the cutting edge of discovery - men and women who may discover how to build wormholes, manipulate entangled photons or build fully functioning time crystals. In short, these scientists may enable an engineer of the future to do what we have so far been only able to imagine - to build a machine that allows us travel back and forward in time at the touch of a button. It could be you! Science fiction? Watch this film.

What if aliens landed on Earth? Much of science fiction explores the moment of first contact – what will people do when the aliens land? From H. G. Wells’ pioneering The War of the Worlds to Independence Day, Men in Black, and District 9, Invasion deals with our fears of alien invasions of earth. David Tennant explains the appeal of Doctor Who’s Daleks and Cybermen while John Carpenter and Chris Carter explore the rich appeal of the paranoia fuelled by hidden aliens with The Thing and The X-Files. It also asks, what if the monsters were our own creation? With the aid of rarely seen animation tests, Phil Tippett takes us behind the scenes in the creation of the dinosaurs of Jurassic Park. But not all invasions are hostile. Peter Coyote and Richard Dreyfuss discuss the creation of Spielberg’s spellbinding classics E.T. the Extra-Terrestrial and Close Encounters of the Third Kind. There is more than one kind of invasion.