Horizon uncovers the secret world of our dreams. In a series of cutting-edge experiments and personal stories, we go in search of the science behind this most enduring mystery and ask: where do dreams come from? Do they have meaning? And ultimately, why do we dream? What the film reveals is that much of what we thought we knew no longer stands true. Dreams are not simply wild imaginings but play a significant part in all our lives as they have an impact on our memories, the ability to learn, and our mental health. Most surprisingly, we find nightmares, too, are beneficial and may even explain the survival of our species.

Ancient Greece's most powerful god wages an epic struggle against his father for control of the universe. It's the ultimate Clash of the Gods as the Olympians challenge the Titans in mythology's greatest showdown. This is a pivotal battle that experts believe may have been ancient code for a real world event - one of the greatest natural disasters the Earth ever experienced.

The tale of the strongest superhero in Greek mythology and his quest for redemption. To atone for committing a heinous crime, Hercules embarks on a series of impossible challenges known as the 12 Labors. Hercules endures as one of history's most influential demi-Gods, but recent archaeological discoveries suggest that mythology's strongest man may have been inspired by a real person.

Go behind the veil of the ancient Greek belief in life after death to explore the myth of their most feared god - Hades - and those mortals who tried to cross his path. It is a chilling collection of tales about Hades and the underworld bearing his name, with eerie links to real world curses, ghosts and secret cults.

A half-bull half-man freak of nature, the Minotaur is one of mythology's most terrifying monsters. A bizarre tale of bestiality, human sacrifice and war, the myth of the Minotaur endures as a symbol of the beast inside all men. But archeological research has uncovered clues suggesting the Minotaur and its terrifying labyrinth were just as much fact as they were fiction. Could they have been inspired by a real place that still exists to this day?

They soar through the heavens, fly through the oceans and glide along land. But these are not creatures found on a wildlife safari. These are life forms from another planet. Armed with scientific fact and a little imagination, experts come together to take you on an unprecedented journey to the edges of our imagination.