Machu Picchu grown rapidly. In 1912, 1914 and 1915, Bingham removed thousands of artifacts from Machu Picchu—ceramic vessels, silver statues, jewelry and human bones—and took them to Yale University for further study, supposedly for 18 months. Yale instead kept the artifacts until 2012, arguing that Peru lacked the infrastructure and systems to care for them. Eliane Karp, an anthropologist and wife of former Peruvian President Alejandro Toledo, accused Yale of profiting from Peru's cultural heritage. Many of the articles were exhibited at Yale's Peabody Museum. In 2006, Yale returned some pieces but kept the rest, claiming this was supported by federal case
Machu Picchu were not perfect, as studies of the land show that there were landslides that happened during the construction of Machu Picchu. It can still be seen where the terraces were shifted by landslides and then stabilized by the Inca as they continued to build around the area. It is estimated that the area around the site has received more than 72 inches of rain per year since A.D. 1450, which was more than needed to support crop growth there. Because of the large amount of rainfall at Machu Picchu, it was found that irrigation was not needed for the terraces.