The Maya established a series of city-states in Southern Mexico and Central America beginning in about 1500 B.C.E. Many would say that theirs was the most advanced of the pre-Columbian cultures of Mesoamerica. The civilization reached its zenith between 250 and 900 C.E. The Maya had a fully developed writing system, a sophisticated calendar, and a knowledge of astronomy. They also were advanced in their architecture, weaving, pottery, and stone carving. And, as did the other Mesoamericans, they built pyramids as part of their religious expression. Mayans continue to live in southern Mexico and Central America and to follow many of their ancient traditions. The Mayan myths are collected in the Popol Vuh.