Sacred stones, or huacas, at the ancient Inca city of Machu Picchu integrated human ritual with the surrounding landscape. I argue that huacas defined the relationship between nature and ritual practice by forcing an esoteric choreography which involved specific postures of the participant in order to visually orient humans to significant natural features of the surrounding environment. Inca stonemasons refined the natural form of the huacas so that they mimic the contours of prominent landscape features such as mountain peaks. This dissertation documents 122 huacas at Machu Picchu using maps of the site to record the exact location of each stone. Every huacas is described in detail, including notation of the specific cardinal orientation; lines of sight established by reference points to prominent landscape features; and the specific posture required to view these lines of sight. The extensive number of huacas at Machu Picchu suggests a highly ritualistic city in which stones and caves were almost certainly considered metaphysical conduits between humans and the divine.