On Periférico Sur, very close to the University City, an unusual pyramid with a circular base stands out: it is the main structure of the Cuicuilco archaeological zone. This is one of the oldest in the capital, since the Cuicuilcas arrived in the Valley of Mexico in 800 B.C., inhabiting it until 250 A.D., when the eruption of the Xitle volcano forced them to flee the area. The history and antiquity of the metropolis can be re-dimensioned when visiting the site museum, whose collection displays the pieces found during the excavation of the area in 1922, and during the construction of the Olympic Village, built to house the athletes for the 1968 Olympics. Climbing the structure changes the perspective of the city; from there, you can see hills, forests, buildings and, on clear days, the small extinct volcano that defined the physiognomy of the southern part of the city.