The citadel of Machu Picchu was constructed around 1450, at the height of the Inca empire. It was abandoned less than 100 years later, as the empire collapsed under the Spanish conquest. The Spanish never found Machu Picchu, and over the centuries surrounding jungle engulfed it. In 1911, American archaeologist Hiram Bingham finally brought the “Lost City of the Incas” to international attention.