Cuicuilco

Cuicuilco is an archaeological site in the southern part of Mexico City that, between roughly 700 BCE and 150 CE, was one of the most important centres of the Valley of Mexico - older than Teotihuacan and with perhaps 20,000 inhabitants at its height. Its emblem is the roughly 23-metre circular stepped pyramid with four concentric tiers and four staircases, an unusual form in Mesoamerica. The site was destroyed by the eruption of the Xitle volcano: lava flows buried much of the city under several metres of basalt, hiding the pyramid until the 19th century. The inhabitants likely fled to Teotihuacan, which then rose to become the dominant metropolis. Today the site lies between urban motorways and the UNAM campus; a small museum explains the preclassic culture and the volcanic disaster.