The modern city of Tula de Allende lies on the edge of the Valley of México, 50km north of Mexico City. A pleasant enough regional centre with an impressive, if fortress-like, mid-sixteenth-century Franciscan monastery and church, it is most notable for the wonderful pre-Hispanic pyramid site of Tula, 2km north of the centre. In legend at least, the mantle of Teotihuacán fell on Tollan, or Tula, as the next great power to dominate Mexico. The Aztecs regarded their city as the successor to Tula and hence embellished its reputation the streets, they said, had been paved with gold and the buildings constructed from precious metals and stones, while the Toltecs, who founded Tula, were regarded as the inventors of every science and art. In reality, it seems unlikely that Tula was ever as large or as powerful a city as Teotihuacán had been or as Tenochtitlán was to become and its period of dominance (about 950–1150 AD) was relatively short.

Yet all sorts of puzzles remain about the Toltec era, and in particular their apparent connection with the Yucatán much of the architecture at Chichén Itzá, for example, appears to have been influenced by the Toltecs. Few people believe that the Toltecs actually had an empire that stretched so far: however warlike (and the artistic evidence is that Tula was a grimly militaristic society, heavily into human sacrifice), they would have lacked the manpower, resources or any logical justification for such expansion. One possible answer lies in the legends of Quetzalcoatl. Adopted from Teotihuacán, the plumed serpent attained far more importance here in Tula, where he is depicted everywhere. At some stage Tula apparently had a ruler identified with Quetzalcoatl who was driven from the city by the machinations of the evil god Texcatlipoca, and the theory goes that this ruler, defeated in factional struggles within Tula, fled with his followers, eventually reaching Maya territory, where they established a new Toltec regime at Chichén Itzá. Though popular for a long time, this hypothesis has now fallen out of fashion following finds at Chichén Itzá that seem to undermine it.

The site itself (daily 9am–5pm) is of interest: though the city spreads over some considerable area only some of it has been excavated, and the outlying digs are holes in the ground, meaningful only to the archeologists who created them. The ceremonial centre, however, has been partly restored. The centrepiece here is the low, five-stepped pyramid of the Templo de Tlahuizcalpantecuhtli (Temple of the Morning Star, or Pyramid B), atop which stand the Atlantes giant, five-metre-tall basalt figures that originally supported the roof of the sanctuary and represent Quetzalcoatl in his guise as the morning star, dressed as a Toltec warrior.

They wear elaborately embroidered loincloths, sandals and feathered helmets, and sport ornaments around their necks and legs for protection, each bears a sun-shaped shield on his back and a chest piece in the form of a stylized butterfly. Each also carries an atlatl, or spear-thrower, in his right hand and arrows or javelins in his left. Other pillars are carved with more warriors and gods. Reliefs such as these are a recurrent theme in Tula: the entire temple was originally faced in sculpted stone, and although it was pillaged long ago you can still see some remnants prowling jaguars and eagles, symbols of the two great warrior groups, devouring human hearts.

In front of the temple is a great L-shaped colonnade, where the partly reconstructed pillars originally supported a huge roof under which, perhaps, the priests and nobles would review their troops or take part in ceremonies in the shade. Part of a long bench survives, with its relief decoration of a procession of warriors and priests. More such benches survive in the Palacio Quemado (Burnt Palace – it was destroyed by fire), next to the temple on the western side.

Its three rooms, each a square, were once covered, with a small central patio to let light in. The middle one is the best preserved, still with much of its original paint and two Chac-mools. The main square of the city stood in front (south) of the temple and palace, with a low altar platform in the centre and the now ruinous pyramid of the Templo Mayor on the eastern side. The larger of two ball-courts in the central area is on the western side of the square: although also largely ruined, this marks one of the closest links between Tula and Chichén Itzá, as it is of identical shape and orientation to the great ball-court there.

To the north of the temple stands the Coatepantli (Serpent Wall), elaborately carved in relief with images of human skeletons being eaten by giant snakes; beyond this, across an open space, there’s a second ball-court, smaller but in better order. The whole significance of the site is made much clearer if your Spanish is up to translating all the information presented in the museum (daily 9am–5pm) located by the entrance, and filled with fragments of Atlantes, Chac-mools and basalt heads, along with assorted bits of sculpture and frieze.