Inca Island in the Sky (E05)

National Geographic Explorer Albert Lin travels to the mountains of Peru to discover the origins of its most famous site, Machu Picchu. Using LiDAR technology Albert finds proof of the people who came before the Inca, and treks high into the mountains to find their homes and ceremonial sites. Gathering the evidence, Albert reveals that the Inca city may have been inspired by another, even older civilisation. (National Geographic)