Teotihuacan has been a mystery for hundreds of years. A city of 150,000 people that was at its peak 1,500 years ago, by the time of the Aztecs 500 years later, no-one remembered who had built the city and why it was abandoned. It became the city of legends and stories.

And even now, with the nest of modern archaeological methods, we still don’t know the ethnic origins of the people who built and lived in this enormous city.

Teotihuacan covers an area of over 16 square kilometres, but most of it is still buried and unexcavated. What has been uncovered in a series of magnificent temples and public buildings, including some of the earliest and biggest pyramids in Central America.


Teotihuacan sits on a plateau 2000 metres above sea level, in the centre of Mexico and near modern Mexico City. 2000 years ago, when the city was built, the plateau was mostly inhabited by an Indian tribe, the Nahuas, who lived in small villages of a hundred or so wattle-and-daub huts. So the leap from these small villages to an enormous city seems remarkable.

The city appears to have been built ready-made as a huge government centre, with enormous temples and ceremonial ways. We can only assume it was built it was built to act as a focal point for people across the plateau of central Mexico, but at a time when these people mostly lived in wooden huts. There had been a civilisation in the region hundreds of years before, the Olmecs, but their civilisation fell apart 500 years before.

Teotihuacan does use similar building styles as earlier cities in the region, but the size and scale of the buildings were unprecedented. The two huge pyramids, the Temple of the Sun and the Temple of the Moon, are both almost 100 metres tall, and are 250 metres on a side. Estimates say it would have taken 3,000 men 30 years to build just one of the pyramids, so that would mean 6,000 men to build the two pyramids. And there are many smaller pyramids and temples, as well as thousands of houses just in the small part of the city that has been excavated.


We don’t know which group of people built the city either. Although some aspects of the city’s culture are obviously developments of earlier known tribes, Teotihuacan is not the product of any of these tribes, and is on a completely different scale to anything built elsewhere in the period.

Teotihuacan was built about AD200 and lasted for several hundred years, but was abandoned and in ruins by AD700. It was not built by the Olmecs, whose civilisation had ended by the first century AD. It was not built by the Toltecs, who came later (arising about AD950). Then the Aztecs followed the Toltecs.

There were small civilisations in nearby parts of Mexico, but they didn’t have the culture or the numbers of people to build a city as huge as Teotihuacan. As a comparison, it was much bigger than Athens during the same period. The style of buildings in Teotihuacan did influence other nearby tribes, but the few that were built in the same style were much, much smaller. The truth is, Teotihuacan stands alone in Mexico at its time – a huge city of 150,000+ people at a time when most of the region was occupied by villages with a few hundred people.

It’s no wonder that some, like Erich van Daniken say that this remarkable city was built by (or with the help of) alien visitors.


The end of the Teotihuacan civilisation is as much a mystery as its beginning. The city exists for hundreds of years with no signs of problems – it was built on a flat plain with no natural defences or fortifications, and archaeologists have found no signs of a major military presence, such as barracks or caches of weapons. Despite other civilisations in ancient Mexico showing evidence of regular warfare, Teotihuacan appears to have been safe from attacks for hundreds of years. And the site was well-watered and fed, surrounded by large and fertile agricultural areas.

So why was the city abandoned?

The period when the city ended was in the 7th century AD, a time known in Europe as the dark Ages, a gap between Roman and Medieval civilisations, and In fact all over the world, civilisation seemed to decline at this period. Now that we understand climate change better, many experts are now theorising that life in many other parts of the world, the climate at Teotihuacan became suddenly worse for several hundred years, affecting crop yields and meaning the local population could no longer support such a big city.

Another theory is that Teotihuacan was obviously the centre of a major religion, and perhaps it was abandoned when that religion lost its influence.

There is some evidence of fires at the end of the city’s life, and that the fires were distributed throughout the city, as if the city was being deliberately torched to stop it being used. This has led to speculation that the Teotihuacan religion was superseded by something else, perhaps because the gods was blamed for the change in climate, and so the centre was destroyed to punish the failed gods.

Of course, some think the Teotihuacan civilisation fell to military conquest, but there are few signs of a military attack, and there are no apparent ethnic groups of the period big enough to have the power to overthrow such a large city.

The Teotihuacan civilisation is still a mystery, appearing from nowhere but disappearing the same way. We will probably never know the truth.