The Valley of Mexico is a highlands plateau in central Mexico roughly coterminous with the present-day Distrito Federal and the eastern half of the State of Mexico. Surrounded by mountains and volcanoes, the Valley of Mexico was a centre for several pre-Columbian civilizations, including Teotihuacan, the Toltec, and the Aztec. The ancient Aztec term Anahuac (Land Between the Waters) and the phrase Basin of Mexico are both used at times to refer to the Valley of Mexico.