Situated along the southern shore of Lake Texcoco (since filled in by the Spanish to create Mexico City), the area around Cuicuilco was settled since at least 2100 BC. But it wasn’t until around 1000 BC that the local inhabitants built the base of the Great Pyramid.
Over the next few hundred years, the main temple platform became rounded, after which additional tiers were added, making it a proper pyramid.
Cuicuilco then quickly became the most dominant city in the Valley of Mexico and remained so for several hundred years. They controlled vast trading route and influenced much of the region’s ceramic styles.
But as nearby Teotihuacan began to grow, Cuicuilco gradually started to decline around 200 BC. And around the turn of the millennium, the area around the Great Pyramid was largely abandoned. The pyramid, however, was still maintained and used as a pilgrimage site.
But how did Cuicuilco’s decline come about? While we don’t know the exact details, the region was likely struck by a series of volcanic eruptions, which gradually depleted local agricultural space, and earthquakes – a threat that still plagues the region to this day. (My initial attempt to visit Cuicuilco in 2017, in fact, was unsuccessful due to the site being closed because of an earthquake.)
The final straw came around 400 AD, when there was a massive eruption from the nearby Xitli Volcano, enveloping the entire area in lava. Interestingly, many of the surviving Cuicuilcans likely fled to Teotihuacan, thus influencing the culture of that great metropolis.
The once-glorious city then remained largely forgotten until its accidental discovery in the 1920s. At the time, workers were quarrying the hardened lava for construction in the capital when they discovered a number of ancient artifacts.
It was then suspected that a local hill in the Pedregal area, long believed to be natural, may have actually been manmade.
In the early 1920s, American archaeologist Byron Cummings excavated the area, confirming that it was indeed a pyramid. But the rock covering it was so hard to dig through that he controversially used dynamite to break it.
Early archaeologists had originally suspected Cuicuilco to be as old as several millennia! Later excavations, however, confirmed that Cuicuilco was not nearly as old as first thought.
Nevertheless, it’s still among the oldest sites discovered in the Valley of Mexico, and surely played an important role in the development of Mesoamerican culture as a whole.