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 an Inca grass rope bridge, across the Urubamba River in the Pongo de Mainique, provided a secret entrance for the Inca army. Another Inca bridge was built to the west of Machu Picchu, the tree-trunk bridge, at a location where a gap occurs in the cliff that measures . The city sits in a saddle between the two mountains Machu Picchu and Huayna Picchu, with a commanding view down two valleys and a nearly impassable mountain at its back. It has a water supply from springs that cannot be blocked easily. The hillsides leading to it were terraced, to provide