Mexico City - Cuicuilco

The Circular Pyramid, erected between 600 and 400 BC and today 18 m (60 ft) high, has a diameter of 112 m (365 ft), and since the eruption of Xitle has been covered and surrounded by lava. During the difficult process of excavation part of the structure was destroyed, and the restoration is of doubtful authenticity. The pyramid seems originally to have been an artificial earth mound, which was subsequently built over on several occasions. The primitive fortress-like style of the pyramid reflects the very beginnings of pre-Columbian monumental religious architecture.

The pyramid consists of five circular tiers of decreasing size, ending in a platform with the remains of an altar. There were probably two staircases leading up to the top of the pyramid, originally 27 m (90 ft) high.

In addition to the principal pyramid excavations have brought to light a further one which could be even older, together with the remains of a horseshoe-shaped altar covered in stones from the river and - to the right of the main entrance to the principal pyramid - a chamber built of stone slabs showing signs of having been painted red. Large numbers of figurines, jewellery and everyday objects of terracotta and stone have also been unearthed. The central deity of Cuicuilco seems to have been the old fire-god Huehuetéotl, who would naturally be associated with the active volcanoes in the surrounding area.

The museum contains finds, mainly terracottas, from the pre-Classic period which are associated with Cuicuilco.

To the south of the site lies the attractive suburb of Tlalpan (Náhuatl, "footprint of man"), a quiet residential area which is also a popular weekend resort. Between 1827 and 1830 it was the capital of México state. It boasts a number of fine colonial buildings, including the 16th c. church of San Agustín de las Cuevas and the 18th c. Casa Chata, which once housed the infamous Inquisition and is now a restaurant.

From Tlalpan the Anillo Periférico Sur leads to Xochimilco, with its "floating gardens".