Cuicuilco

Cuicuilco was the first city in the Basin of Mexico to build monumental architecture, centuries before Teotihuacan. Settled as a farming village, it grew into a regional capital between about 800 BC and AD 250, and at its height, from around 200 BC, covered some 400 hectares with perhaps 20,000 people, with temples, rulers' platforms, waterworks, fields and neighbourhoods of houses. It controlled trade routes towards the valleys of Morelos and Toluca, and its people honoured Huehuetéotl, the old god of fire. Its name, given later by the Mexica, is usually read as the place where people sing and dance.

Around AD 250 the nearby Xitle volcano erupted and buried the city under lava, in places 9 to 10 metres deep, creating the rocky Pedregal that still shapes the south of Mexico City; the survivors seem to have scattered towards Teotihuacan and Toluca. What remains in the INAH zone is about 60 hectares around the Gran Basamento, the main pyramid. Unusually, it is round: five stacked tiers shaped like truncated cones, more than a hundred metres across, reached by ramps on the east and west sides. On the summit archaeologists found a series of oval altars, some coated with red pigment that looks like cinnabar.

A visit means walking up the ramp to the flat top for a view that takes in the Olympic Village and the office towers and shopping centres built over other parts of the ancient city, a reminder of how much was lost to roads, the 1968 Olympic works and later malls. Near the base are the Kiva, a circle of basalt slabs with traces of red paint, a 3.9 m stone stela carved with 16 circles, and Building E-1. The small site museum, 40 metres south of the pyramid, dates from the 1970s and shows pottery, stone tools, shell and burials found at the site. Entry is free, and the open grounds feel surprisingly calm for a site boxed in by some of the city's busiest roads.