Machu Picchu is an ancient Inca ruin, located between two peaks: Machu Picchu, which is known as the ‘Old Peak’, and Huayna Picchu, the ‘New Peak’. At an elevation of 7710 feet, the dwellings at Machu Picchu were probably built and occupied from the mid-15th to the early or mid-16th century, and based on skeletal and material remains, many researchers come to the conclusion that Machu Picchu was built to serve as a royal retreat, although its purpose is unknown. Machu Picchu’s southern, eastern, and western portions are surrounded by many stepped agricultural terraces that used to be watered by an aqueduct system. The reason for the site’s abandonment is also unknown, but some researchers think that the lack of water may have been a main factor. Even now, Machu Picchu remains a mysterious and impressive Inca site, with its purpose, construction, and eventual abandonment still subjects of debate among researchers.