Located in the Cusco region of Peru at 2,400m above sea level, lie the ruins of Machu Picchu, the most familiar icon of the Inca civilization. Most archaeologists maintain that Machu Picchu was built in the 15th century as an estate for the Inca emperor Pachacuti (1438–1472). However, local legends denote that Machu Picchu was a sacred place built far earlier than that. The site is comprised of more than 200 buildings, temples, houses, pathways, fountains and altars all cut from grey granite from the mountain top. Polished dry-stone walls stretch throughout the estate and dozens of terraces have been carved into the mountainside. While the Inca civilization collapsed following the invasion of the Spanish conquistadors, the marvel of Machu Picchu lies in the fact that it was never discovered by the Spanish, and thus it has remained remarkably well-preserved over the centuries.