WHY do we dream? Why do we always wake up just as its getting to the interesting bit? And will I ever relive that night of passion with The Nolans?Tonight, Horizon uncovers the secret world of our dreams as, in a series of cutting-edge experiments and personal stories, we go in search of the science behind this most enduring mystery.Where do dreams come from? Do they have meaning? And ultimately, why do we have them? More pertinently, why can you never remember them in the morning?What the documentary reveals is that much of what we thought we knew about dreams no longer stands true.Many believe they are simply an unburdening exercise, a chance for the mind to empty itself of various distractions, to investigate nagging concerns, like what is the interior décor of Fergie’s bedroom. But in fact it seems 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. Believe me, having a dream about Norman Tebbit certainly sharpens up your performance the next day.Sadly, with the focus being entirely on humans, there is no time left for any examination of dreams in the animal kingdom.Budgerigar owners are once again left answerless as to what occupies their birds’ minds when they slip off into the land of nod.