Machu Picchu is the remnants of an Inca civilization built in the 15th century high in the Andes mountains of modern-day Peru. It was abandoned in the 16th century when the Spanish conquered the Inca empire. The site consists of stone structures including temples, houses, and sanctuaries. It was used as an agricultural center, residential town, and sacred place for worship and trade. The Inca built terraces and developed a sophisticated irrigation system to farm the steep mountainsides. Machu Picchu was rediscovered by the outside world in 1911 and is now Peru's most visited tourist attraction.