Descending into the Underworld of Teotihuacan: Labyrinthine Tunnels and Rivers of Mercury
The location of the main cave system, a few hundred meters to the East of the Pyramid of the Sun (visible in the distance). (Photo by author Marco M. Vigato)
Over the course of the 1990s and early 2000s, archaeologist Linda Manzanilla of the Autonomous University of Mexico led a comprehensive examination of the caves and tunnels under Teotihuacan. She reached the conclusion that the vast majority of the tunnels accessible today were man-made, and not natural lava tubes. She suggested they had most likely originated as quarries, but were later used for a number of funerary and ritualistic purposes.
The two images above show some of the caves present extensive burn marks on the walls and ceilings, which testify of a long and intense ritual activity. (Photos by author Marco M. Vigato)
Descending into the Underworld
In the early months of 2017 I was able to personally explore a section of the tunnels located less than a few hundred meters to the east of the Pyramid of the Sun. Most of the entrances and side passages have been blocked in modern times, but it is still possible to follow their course for a short distance.
In the “Cueva del Pirul”, one of the largest systems of interconnected caves to the East of the Pyramid of the Sun. (Photo by author Marco M. Vigato).
Some more tunnels branch out from a vast chamber resting on rough rock-cut columns or pillars. One of those can be followed for a distance of perhaps 50 or 60 meters (164 – 196 feet) until a pit from where more passageways branch out. The loose conglomerate that forms the walls and ceiling of the tunnels and chambers does not encourage further exploration for the risk of cave-ins. Even in their present dilapidated condition, the tunnels follow a regular plan with fairly constant height and width. It is possible that some of the deeper tunnels continue under the much harder basalt bedrock, as the ones visited and described by Charnay in 1880. The existing tunnel entrances could thus represent an attempt by later occupants of the site to penetrate a much deeper and perhaps far older labyrinth.
In the “Cueva del Pirul”. (Photo by author Marco M. Vigato).
Rivers of Mercury
For the inhabitants of Teotihuacan, the labyrinthine network of caves and tunnels under the city represented the entrance to the Underworld. In the Codex Xolotl , the glyph used to represent Teotihuacan contains the depiction of two pyramids above a cave with a person inside. This suggests a possible connection with the Aztec traditions of Chicomoztoc, the “ Place of the seven caves ”, from which the present humanity was said to have emerged after a previous world was destroyed.
Some of the caves to the East of the Pyramid of the Sun have collapsed since ancient times, leaving large openings in the ceiling that partially illuminate the interior. (Photo by author Marco M. Vigato)
In 2003, the entrance to a previously unknown tunnel was discovered under the pyramid of Quetzalcoatl. The tunnel ran about 100 meters (328 feet), and had been intentionally sealed with large boulders in antiquity. Archaeologist Sergio Gomez has since described the tunnel as “one of the most important discoveries in the history of Mexico”. The tunnel, with continued exploration, has since revealed over 50,000 artifacts. Particularly puzzling has been the discovery in 2013 of hundreds of metallic spheres, ranging from 4 to 12 cm (1.57 to 4.7 inches) across. The spheres appear to have been covered in pyrite, while a core of clay and other unidentified compounds.
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At the end of the tunnel lies what is likely a system of three chambers, still awaiting exploration. In one of the chambers, vast quantities of liquid mercury were detected. Gomez speculates that these veritable “pools” of liquid mercury could have symbolized an underworld river or lake.
Traces of Immortality?
Many ancient civilizations, particularly the Chinese, considered mercury a vehicle for immortality. However, due to its high toxicity and complex extraction, the discovery of liquid mercury is extremely unusual at ancient sites, and is virtually unparalleled in Mesoamerica. If the caves and tunnels of Teotihuacan were designed as a symbolic representation of the Underworld, it is very well possible that the new tunnels recently discovered under the pyramid of the feathered serpents could one day lead to a mythical tomb, perhaps the final resting place of mysterious ruling elite responsible for the construction of Teotihuacan and for the monumental megalithic architecture present at the site.