The ancient civilization that built the Machu Picchu citadel in the Andes Mountains is the Inca civilization. Established in the early 15th century, the Incas developed a sophisticated society noted for its impressive architectural achievements, agricultural innovations, and extensive road networks. Machu Picchu, constructed in the 1450s, served as a royal estate or religious site and is renowned for its intricate stonework and breathtaking mountain landscape. Rediscovered in the early 20th century, it has since become a UNESCO World Heritage Site and is one of the most iconic symbols of Inca heritage and Andean history.