Hiram Bingham III was the only historian of Latin America in the United States in the early twentieth century. As such, he went to a variety of places throughout South America, and in Peru he was told of significant lost Inca cities. So in the summer of 1911, Bingham led an expedition from Yale to the Andes to find these places. He had a great deal of success at finding significant sites, but this expedition would become famous for going to a plateau nearly 8,000 feet above sea level, near a peak called Machu Picchu. There, he discovered a massive, impressive city built entirely by the Incas and never touched by the Spanish. This was important, because most of the key examples of Inca architecture were damaged in the Spanish conquest. Bingham thought the site was a religious center, but he was wrong. Machu Picchu was built by the significant Inca ruler Pachacuti as a royal retreat. Still, the ability to research the use of Machu Picchu was only possible because Hiram Bingham announced to the world that Machu Picchu existed, even if he did not always act as appropriately as people would have liked.