The circular temple of Cuicuilco is the oldest construction of such large scale in central Mexico. The settlement is at least 3400 years old. The site is not as impressive as some of the other Mexican pyramids, but it is one of the most important ruins in all of Central America.
Cuicuilco is an often debated site among archaeologists. This is due to the fact that some experts claim the circular pyramid is more than 10,000 years old.
Not much is known about this site which was partially buried by the eruption of the volcano Xitle and which has almost been completely covered by the construction of new buildings.
This circular temple is commonly accepted as among the oldest in the Valley of Mexico. Parts of the large and complex site are buried by ash from volcanoes as recently as 300 AD, while other parts are buried under volcanic ash that are said to have been dated as 8,000 years old. Most archaeologists do not support the 8,000 year old date. One eruption is actually carbon dated at about 30 AD.
There are those who claim that 150 BC was the year of the great „consternation“ that destroyed Cuicuilco. But actually Xitle, according to Alva Ixtlilxochitl, „opened the earth and swept everything in its path, on the day Ahui-Quiahuitl, in the year 8-Tecpatl.“ This translates into April 24, 76 AD.
Cuicuilco was abandoned at the time of the eruption of the volcano Xitle in about 30 AD. This was about the same time that Teotihuacan was beginning to develop. There are numerous discussions which claim that the destruction of Cuicuilco caused the growth of Teotihuacan.
The massive circular pyramid is composed of three sloping tiers which are approached by a ramp and a stairway and it has a base 387 feet in diameter with a height of 75 feet.