In ancient, pre-literate cultures across the globe, tribal elders had encyclopedic memories. They could name all the animals and plants across a landscape, identify the stars in the sky and recite the history of their people. Yet today, most of us struggle to memorize more than a short poem. Using traditional Aboriginal Australian song lines as a starting point, Lynne Kelly has since identified the powerful memory technique used by our ancestors and indigenous people around the world. In turn, she has then discovered that this ancient memory technique is the secret purpose behind the great prehistoric monuments like Stonehenge, which have puzzled archaeologists for so long. The stone circles across Britain and northern Europe, the elaborate stone houses of New Mexico, huge animal shapes in Peru, the statues of Easter Island - these all serve as the most effective memory system ever invented by humans. They allowed people in non-literate cultures to memorize the vast amounts of information they needed to survive. But how? For the first time, Lynne Kelly reveals the purpose of these monuments and their uses as 'memory places', and shows how we can use this ancient technique to train our minds.