Machu Picchu National Geographic again and with the full support of Peruvian President Leguia. The expedition undertook a four-month clearing of the site with local labour, which was expedited with the support of the Prefect of Cuzco. Excavation started in 1912 with further excavation undertaken in 1914 and 1915. Bingham focused on Machu Picchu because of its fine Inca stonework and well-preserved nature, which had lain undisturbed since the site was abandoned. None of Bingham's several hypotheses explaining the site held up. During his studies, he carried various artifacts back to Yale. One prominent artifact was a set of 15th-century, ceremonial Incan
Machu Picchu then crossed a pass and into the Pampaconas Valley where he found more ruins heavily buried in the jungle undergrowth at Espíritu Pampa, which he named "Trombone Pampa". As was the case with Machu Picchu, the site was so heavily overgrown that Bingham could only note a few of the buildings. In 1964, Gene Savoy further explored the ruins at Espiritu Pampa and revealed the full extent of the site, identifying it as Vilcabamba Viejo where the Incas fled after the Spanish drove them from Vitcos. Bingham returned to Machu Picchu in 1912 under the sponsorship of Yale University and