The art of Central and South America from 1800 BC to 1500 AD, prior to the arrival of European colonizers, is genially called Pre-Columbian Art. The Olmec civilization flourished around 1200–400 BC. The Olmecs produced jade figurines, and created heavy-featured, colossal heads, up to 2 meters (8 ft) high, that still stand mysteriously in the landscape. From ca. 200–900 AD the dominant culture was the Maya. The Maya had advanced astronomy and their own forms of hieroglyphic writing. Mayan art utilized glyphs and stylized figures decorate architecture such as the pyramid temple of Chichén Itzá. During a long reign of Pacal the Great (603-683) the Maya polity of Palenque saw the construction or extension of some of most notable surviving inscriptions and monumental architecture. The Post-classic period (10th–12th centuries) was dominated by the Toltecs who made colossal, block-like sculptures such as those employed as free-standing columns at Tula, Mexico. The Aztec people of central Mexico dominated large parts of Mesoamerica in the 14th-16th centuries. The Aztec culture produced some dramatically expressive examples of Aztec art, such as the decorated skulls of captives and stone sculpture. Among the cultural traits that the Aztecs of Tenochtitlan shared with many other cultures of central Mexico are the complex religious beliefs and practices including most of the pantheon (e.g. gods such as Tezcatlipoca, Tlaloc and Quetzalcoatl), the calendar system of a xiuhpohualli of 365 days intercalated with a tonalpohualli of 260 days. In South America, at the time of the Spanish conquest the Inca Empire was the largest and wealthiest empire as depicted in their art. The Inca valued gold among all other metals, and equated it with the sun god Inti. Some Inca buildings in the capital of Cusco were literally covered in gold, and most contained many gold and silver sculptures. It is a cultural tragedy that most Inca sculpture was melted down by the invading Spanish.