Hancock also believes that the great temples of Angkor Wat in Cambodia mirror the constellation Draco as it would have appeared 12,000 years ago - at a time when the world was in the Stone Age. They see this as evidence that a great civilisation existed at this time, and later conveyed its wisdom to the peoples of the ancient world, before disappearing without trace from the archaeological record. Astronomers, archaeologists and geologists study this evidence. Dr. Ed Krupp of the Griffith Observatory in Los Angeles, is troubled by Bauval's claims. Horizon further examines Hancock's claims that the Sphinx and the mysterious ancient city of Tihuanacu in Bolivia were built 12,000 years ago by survivors of the lost civilisation itself. Divers at the Yonaguni formation It considers the idea that either Antarctica or an extraordinary underwater site at Yonaguni in Japan were the original home of these vanished people. In a film full of contentious debate and powerful arguments, Graham Hancock's claims are pitted against cutting edge scientific analysis to discover whether his popular theory could be true.