By Research Professor Saburo Sugiyama

The decline of the Teotihuacan state was rather quick. Evidence for possible threats has been recovered from the city’s residences.

Thick, high walls were integrated into architectural complexes: a wide, deep canal system and high platforms may have functioned as defensive facilities. Roughly-made stone walls blocked access to many residential complexes in the final architectural stage. The way in which the walls were constructed gives the impression that the inhabitants suddenly needed to strictly control access to residences.

The evidence of Teotihuacan’s final destruction is unmistakable. Evidence of fires on the floors and walls of residences is conspicuous, and evidence for conflict increases as excavations progress.

Many temples, pyramids and high-quality residential compounds seem to have been burned. It was a long-standing tradition in Mesoamerica to set fire to the temples of conquered areas.

We still do not know exactly when this happened, or who did it. However, we assume that the disintegration of the Teotihuacan state took place essentially as a consequence of political conflict that probably involved military forces, rather than natural disasters.

One room of the "palace"-type complex attached to the west of the Pyramid of the Moon was excavated by the Pyramid of the Moon Project in 2001. A large amount of charcoals was found just above the burned floor.