Often referred to as "The Lost City of the Incas", Machu Picchu is one of the most familiar symbols of the Inca Empire. The Incas started building it around AD 1430 but was abandoned as an official site for the Inca rulers a hundred years later at the time of the Spanish conquest of the Inca Empire. Although known locally, it was largely unknown to the outside world before being brought to international attention in 1911 by Hiram Bingham, an American historian. Since then, Machu Picchu has become an important tourist attraction.