The Inca civilization only lasted a few centuries from about 1200 CE. In that short period it became the largest empire in pre-Columbian America. It emerged in the Andean region of present-day Peru. The early Incas established the city of Cusco as their capital. They expanded rapidly, by the 15th century they developed an extensive network of roads, sophisticated agricultural terraces, and monumental architecture, such as Machu Picchu. They developed a system of record-keeping using quipus (knotted strings) and a calendar based on the movements of the sun and moon. The Inca Empire fell to Spanish conquistadors in 1533, leading to its dissolution, but the cultural legacy endures among Andean communities.