No one knows for sure who built this mighty pre-Hispanic city of around 20,000 inhabitants (The Totonacs? The Huastecs?), which is why archaeologists refer to the civilization as Classic Veracruz. But one thing's for sure: this site, dating back to AD 800 and discovered by accident in 1785, is one of the most atmospheric, best-preserved and most thoroughly excavated pre-Hispanic cities in Mesoamerica. Seven kilometers away from Papantla, El Tajín's extensive ruins are easily reachable by frequent bus (M$20). The El Tajín site covers an area of about 10 sq km. You’ll need at least a couple of hours to take in all the highlights. There’s little shade and it can get blazingly hot, so come early or late and bring a hat and water. There is labeling in English, Spanish and Totomec in front of most important buildings, but it's worth getting a guide (M$300 per hour) if you want to know all the details. Highlights include the beautifully proportioned Pirámide de los Nichos. Just off the Plaza Menor, it's a six-tiered pyramid, with each tier featuring rows of square niches, believed to have been used as a solar calendar. Of the 17 ball courts that have been found at El Tajín, the Juego de Pelota Sur is the most famous, due to the six relief carvings on its walls, depicting deities, the cosmos and ball players. North of, and slightly uphill from, the main site, El Tajín Chico was where the city's ruling classes lived and governed. Many of the buildings here display geometric stone mosaic patterns known as ‘Greco’ (Greek), and it's best not to miss Edificio I, believed to have been a palace, with its unusual carvings and well-preserved paintwork.