Archaeologists may be a step closer to discovering the secrets of the ancient city of Teotihuacan: They have unearthed liquid mercury deep beneath the Mexican Pyramid of the Feathered Serpent. The “large quantities” of the toxic liquid metal leads researchers to believe that an undiscovered ancient ritual chamber or even the tomb of a king could rest below the ruins of the ancient city that sits about 30 miles from Mexico City, reports Reuters.
On Friday, The Guardian reported that researcher Sergio Gómez stumbled upon the liquid mercury after six years of gradually uncovering a tunnel underneath the Teotihuacan pyramids.
The city, dubbed the abode of the gods in the ancient language Nahuatl, was once the nucleus of an empire. About 200,000 people are thought to have lived there between 100 and 700 A.D., until its residents mysteriously hightailed it away. The city remained largely intact, but much is unknown about its people, how life flourished there and who was in the seat of power. Also unknown is whether power was passed down through a dynasty or if the ruler was an overlord.
Due to thick humidity and mud in the area, few excavations have been attempted at the site. The Spaniards did so in the 17th century, but no real progress was made until the 20th century.
Upon unsealing the tunnel in 2003, Gómez and his team dug up treasures including jaguar remains, enormous seashells, jade statues and rubber balls. The team in November 2014 discovered three chambers at the end of the tunnel, which had remained intact for about 1,800 years.
For now, it’s unclear how the Mesoamericans living in Teotihuacan used the metal. But it’s also been found in other excavations throughout Central America, specifically in Mayan ruins farther south. Mercury, which is highly poisonous, was regarded as a rarity among Mesoamerican people, and may have borne ritualistic significance given its reflective properties.
In an interview with Reuters, Gómez said the mercury, which may have been used to symbolize an underworld body of water, could possibly lead researchers on a path to a royal tomb long believed to sit underneath Teotihuacan. The speculation isn’t mercurial on their part: In Mesoamerican lore, reflective surfaces, such as mirrors, functioned as portals into both the future and as the river that they believed carries us all after death, something not unlike the Styx from Greek mythology.
Much work remains to be in done digging out the tunnel, and with uncoding the hieroglyphics scattered throughout the city. But Gómez believes the team will complete its dig by October, and an announcement of the findings is expected later in 2015. U.S. archaeologist George Cowgill, who’s devoted his life to unearthing the site, said the mercury find is just the beginning. “It’s still very uncertain, and that is what keeps everybody in suspense,” he told Reuters.
Clarification: An earlier version of this article stated that the river from mythological lore was the Styx. This article has been amended to reflect that Mesoamerican lore believes that reflective surfaces, such as rivers, can be portals into supernatural realms and symbolize death, such as the river Styx from Greek mythology.