It is thought the city was built by the Inca emperor Pachacuti[?] starting in about 1440 and was inhabited until the Spanish Conquest[?] in 1532. Archeological evidence (together with recent work on early colonial documents) shows that it was was not a conventional city; rather it was rather a sort of country retreat town for the Inca Emperor and nobility. The site has a large palace and temples around a couryard, with other dwellings for the support staff. It's estimated that a maximum of only about 750 people resided in Machu Picchu at any one time, and probably only a small fraction of that number during the rainy season and when no nobles were visiting.
The city was re-discovered on July 11, 1911 by a Yale historian, Hiram Bingham[?] who was exploring old Inca roads in the area. Bingham made several more trips and conducted excavations on the site through 1915. He wrote a number of books and articles about Machu Picchu; his popular account "Lost City of the Incas" became a best seller.
In 1913 it received a significant amount of publicity after National Geographic Society devoted their entire April 1913[?] issue to Machu Picchu.
The site is UNESCO World Heritage Site and a popular tourist attraction.