Cuicuilco: the circular pyramid buried by lava in southern Mexico City

Just steps from the Perisur shopping mall and the traffic of the Periférico, in the Tlalpan borough south of Mexico City, there's an archaeological site that most tourists skip on their way to Teotihuacán or the Templo Mayor. Cuicuilco is a different choice: one of the oldest cities in the Valley of Mexico, inhabited from around 700 BC and grown to several thousand inhabitants between 150 BC and the first centuries AD, before Teotihuacán.

The circular pyramid

The main draw is the Gran Basamento, a circular-plan pyramid about 25 metres high with a base diameter of around 120 metres. The circular shape is unusual in Mesoamerican architecture, which almost always uses rectangular bases, and that alone makes the visit interesting. The structure is built as superimposed truncated cones of stone and earth; a ramp lets you climb to the summit, from which you take in much of the archaeological zone and, in the background, the profile of the volcanoes.

The Xitle lava

What preserved the site is also what doomed it: the eruption of the Xitle volcano, a small cone on the slopes of the Ajusco. The flow covered the area with a layer of basalt that in places reaches ten metres thick, creating the expanse of black rock now known as the Pedregal de San Ángel. The exact date of the eruption is still debated among scholars, but the effect is clear: the lava sealed the city, forcing its inhabitants to abandon it and freezing the structures under the stone. Part of that pedregal is still visible as you walk through the site.

The park

Beyond the pyramid, the area is an eco-archaeological park with trails crossing vegetation typical of the highlands: pirules (the false pepper trees), nopales and other succulents, agaves, with birds and squirrels. Even though the setting is entirely metropolitan — buildings, interchanges, and malls all around — the site remains surprisingly quiet and little visited, especially on weekdays. There is also a free Museo de Sitio, with ceramics, models, and maps reconstructing the life of the city and its relationship with the volcano: useful to see before or after the walk among the ruins.

Practical information. Admission to the site and the museum is free. Indicative hours are Tuesday to Sunday, from 9:00 a.m. to 5:00 p.m. (closed Monday); the use of a video camera may be subject to a fee. The ground is uneven and partly rocky, so walking shoes are advisable; animals, bicycles, and scooters are not allowed. It's worth bringing water and a hat, since there is little shade on the pyramid.

Getting there

Getting there. The site is at the junction of Avenida Insurgentes Sur and Periférico Sur, in the colonia La Joya, opposite the Villa Olímpica. The easiest way without a car is the Metrobús Línea 1 (Insurgentes), getting off at the Villa Olímpica or Perisur station and reaching the entrance on foot. Alternatively, from Metro Universidad or Ciudad Universitaria you can take southbound transport along Insurgentes. It combines easily with a visit to San Ángel or to the Ciudad Universitaria of UNAM, which are nearby. Half a day is enough to see the site and the museum at a relaxed pace.