fortified ancient city known for its impressive ruins. It is located on the top of a large hill and parts of surrounding hills near Cuernavaca, in Morelos state, Mexico.

Xochicalco was built after the fall of Teotihuacán primarily during the 8th and 9th centuries AD. Its ruins reveal multicultural influence, including Aztec, Zapotec, and Olmec elements. Xochicalco soon became an important trading centre, its strategic location making it an entrepot for goods from the Pacific coast, Puebla, Tlaxcala, and more distant regions. The reason for the city's decline is a matter of speculation.

Excavations, begun in 1909, have revealed a number of structures, including the so-called Pyramid of the Feathered Serpent ( Quetzalcóatl), two ball courts, and a variety of houses and plazas. The Pyramid of the Feathered Serpent displays a number of reliefs—such as plumed serpents and men with elaborate headdresses—indicating strong Mayan influence. Xochicalco was declared a UNESCO World Heritage site in 1999.