The Inca Empire spanned over 4,000 miles along the western coast of South America, with its capital at Cuzco and religious center at Machu Picchu. The Inca developed advanced agricultural systems using terracing and irrigation to grow crops in the mountains and jungles. Inca society was organized into clans under the rule of a centralized government based in Cuzco, which employed administrators to govern its diverse territories. The Incas lacked a written language but used knotted strings to record and communicate information.