Hiram Bingham III Stuart McNairn whose descendants claim that they had already climbed to the ruins in 1906). Also the Cusco explorers Enrique Palma, Gabino Sanchez and Agustín Lizarraga are said to have arrived at the site in 1901. Bingham returned to Peru in 1912, 1914 and 1915 with the support of Yale and the National Geographic Society. In "The Lost City of the Incas" (1948), Bingham related how he came to believe that Machu Picchu housed a major religious shrine and served as a training center for religious leaders. Modern archaeological research has since determined that the site was not a religious
Machu Picchu push the stones up inclines. A few stones have knobs that could have been used to lever them into position; the knobs were generally sanded away, with a few overlooked. The Inca road system included a route to the Machu Picchu region. The people of Machu Picchu were connected to long-distance trade, as shown by non-local artifacts found at the site. For example, Bingham found unmodified obsidian nodules at the entrance gateway. In the 1970s, Burger and Asaro determined that these obsidian samples were from the "Titicaca" or Chivay obsidian source, and that the samples from Machu Picchu showed long-distance