Horizon: Why Do We Dream?

An investigation into the science behind dreams, using a series of cutting-edge experiments and personal stories to discover where they come from, whether they have meaning and, ultimately, why we have them. The film reveals 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 - from our memories to the ability to learn and our mental health. Most surprisingly, we find nightmares are also beneficial and may even explain the survival of our species.