The ancient city of Teotihuacan has since been excavated and studied by archaeologists, many travelling from the US and around the world to learn about how the Aztecs once lived and ruled.
One surprising discovery made beneath the largest pyramid in the city, the Pyramid of the Sun, was explored during Discovery’s short documentary, ‘Shocking Artefacts And Human Remains Found In 2000 Year Old Pyramid’.
Here, archaeologists unearthed a tunnel in the bedrock, at first believing that it was a natural cave.
Temple of the Feathered Serpent: Some of the detailing on the pyramid’s exterior (Image: GETTY)
However, on further investigation, they hit a carved out chamber, and beyond it the remnants of 17 thick man-made walls, built to block access to the tunnel.
At the very end of the tunnel, they fund an elaborate chamber carved in the shape of a clover.
Now, the tunnel lies empty, likely stripped of its contents by robbers over the centuries.
But, the discovery under the Sun pyramid was just the beginning: in 2003, a tunnel was discovered beneath the Feathered Serpent pyramid.
Then, in 2017, Mexican archaeologist Sergio Gómez uncovered another secret tunnel under the Feathered Serpent pyramid.
This tunnel appeared untouched by thieves as Sergio and his team discovered more than 100,000 different objects.
He said: “Extraordinary objects, some of them never seen before in any Mexican archaeological exploration.”
Undisturbed for 1,800 years, the objects were found lying exactly where they had first been placed as ritual offerings to the gods.
Some of the pieces unearthed included greenstone crocodile teeth, crystals shaped into eyes, and sculptures of jaguars ready to pounce.
Human remains: A chamber was found filled with human remains laid out in a ‘symbolic’ pattern (Image: Youtube/Discovery)
Above the intricate system of tunnels, at the heart of the pyramid, excavations revealed a darker secret: the remains of countless humans.
Anthropologist Saburo Sugiyama examined the myriad bones unearthed from the ancient city of Teotihuacan.
He said: “Human bones tell us a lot of things: male, female, how many years they had when they died, how they lived, how they died.”
He believes the bones found may be evidence of gruesome human sacrifice, with the biggest clue coming from the way in which the bones were found.
Archaeological discoveries: Some of the most groundbreaking discoveries on record (Image: Express Newspapers)
Archaeologists stumbled across them while tunnelling deep inside the body of the pyramid.
Inside the Feathered Serpent’s pyramid, at its centre, is a “dark secret”: 20 skeletons, almost completely intact, carefully arranged in what looks like a “symbolic pattern”.
They were not alone, as in total, over 260 bodies were found to be built unto the fabric and foundation of the building.
The narrator noted: “The pyramid is a mass grave.”