The Avenue of the Dead, with the Pyramid of the Sun to the left. (Photo: eu tirada/Public Domain)

Teotihuacán is mysterious. A city that probably started around 400 B.C., before it was abandoned over 1,000 years later, this central Mexican civilization has long puzzled archaeologists, as Teotihuacanos seemingly left no written records. 

Were they ruled by a single, all-powerful king? Or was it a council? What was their religion? What language did they speak? We simply don’t know. 

But 13 years ago, as Matthew Shaer reports in Smithsonian, an archaeologist who has devoted his entire career to the Teotihuacanos stumbled upon a secret: a tunnel, specifically, that no one knew existed before. It was built under a temple in the city. 

Six years later, the archaeologist, Sergio Gómez, began excavating. What he uncovered was a trove of artifacts, from necklaces to knives to bones. And Gomez might find more: there are three chambers still to be excavated. 

The tunnel was apparently not supposed to be found. Boulders blocked its entrance, and Gómez says that he thinks it was meant to be sealed forever.

Some had thought Gómez might find a tomb, lending credence to the theory that Teotihuacanos were led by a single ruler. But while no proper tomb has yet been found, the archaeologist thinks of the tunnel and its chambers as a “symbolic ‘tomb’: a final resting place for the city’s founders, of gods and men,” as Shaer writes.

As for the artifacts? Two stick out: a pair of black stone statues that Gómez says might have stood in for Teotihuacanos’ Creators, objects to be worshiped. The rest will be studied for decades, unlocking the secrets of Teotihuacán one necklace at a time.