The twenty-metre-high pyramid in the main square at Tenayuca, a suburb just outside the city limits, is another site that predates Tenochtitlán by a long chalk. Indeed, there are those who claim it was the capital of the tribe that destroyed Tula. In this, its history closely mirrors almost all other valley settlements: a barbarian tribe from the north invades, conquers all before it, settles in a city and becomes civilized, borrowing much of its culture from its predecessors, before being overcome by the next wave of migrants. There’s little evidence that Tenayuca ever controlled a large empire, but it was a powerful city and provides one of the most concrete links between the Toltecs and the Aztecs.

The site

The pyramid that survives dates from the period of Aztec dominance and is an almost perfect miniature replica of the great temples of Tlatelolco and Tenochtitlán. Here the structure and the monumental double stairway are intact – only the twin sanctuaries at the top and the brightly painted decorations would be needed for it to open for sacrifices again tomorrow. This is the sixth superimposition; five earlier pyramids (the first dating from the early thirteenth century) are contained within it and are revealed in places by excavations which took place in the 1920s. Originally there was a seventh layer built on top, of which some traces remain.

The most unusual and striking feature of Tenayuca’s pyramid is the border of interlocking stone snakes that must originally have surrounded the entire building – well over a hundred of them survive. Notice also the two coiled snakes (one a little way up the north face, the other at the foot of the south face) known as the “turquoise serpents”. Their crests are crowned with stars and aligned with the sun’s position at the solstice.