Halfway between Machu Picchu and the city of Cuzco, Peru, lies a civil engineering wonder that has captivated and puzzled researchers and travellers since it was first photographed in 1931. Situated on a plateau, the ancient Inca site of Moray consists of many terraced circular depressions in the earth, the largest of which is 30 meters deep. This reports the results of an exhaustive investigation into the surveying work underlying the site's construction, as well as the engineered systems for collecting and delivering water.