There are thousands of pyramids scattered across the globe. Pyramids were erected in nearly all continents on Earth by different cultures throughout history. But many secrets about the pyramids remain hidden not inside them, but deep beneath their very foundations.

The most famous pyramids are those built on the Giza Plateau, where the pyramids of Khafre, Menakure, and Khufu stand proudly, guarded by the mighty Sphinx.

Although the most famous, they are certainly not the oldest, nor largest pyramids built on the planet.

The largest pyramid is the so-called Great Pyramid of Cholula, located in Puebla, Cholula, modern-day Mexico. Measuring a total of 160,000 square meters, the Pyramid of Cholula has three times the area of the 53,056.5 square meter base area of the Great Pyramid at Giza.

Having a total estimated volume of 4.45 million cubic meters, the Great Pyramid of Cholula was a pyramid that was worthy of the most impressive monuments in the world, even larger than the great pyramid of Giza, in Egypt, which contains an approximately 2.5 million cubic meters.

But Cholula is one of the many pyramids that exist on Earth, and there are other fine examples of Pyramid building are found in Mexico.

Join me in this excerpt from my upcoming book, Pyramidomania – A World of Pyramids, as I explore the mysteries of Teotihuacan, its mysterious ancient pyramids, and the massive underground world beneath.

I am Ivan Petricevic, and here are some of the most fascinating details about Teotihuacan’s underground world.

Teotihuacan and its subterranean world

One of the most important ancient cities constructed in pre-Columbian America is Teotihuacan.

Once, one of the largest cities in the world, inhabited by more than 150,000 people the city of Teotihuacan is home to a mind-bending set of structures, and where an ancient culture shrouded in mystery built the most architecturally significant Mesoamerican Pyramids in pre-Columbian America.

It is believed that Teotihuacan was home to more than 2,000 labyrinthine housing complexes, including artisan workshops, markets, and temples.

Its mysterious ancient builders constructed a ceremonial center that could hold up to 40,000 people where different religious ceremonies were performed in honor of the god of the sun, the moon, the rain as well as their most important deity, Quetzalcoatl, the plumed serpent.

The city is home to some of the most impressive examples of ancient architecture in the world. Home to a massive central road dubbed the “Avenue of the dead.”

When viewed from the air, it becomes clear that Teotihucan’s builders planned the city to the most minimalistic detail, resulting in a massive ancient metropolis covering 8 square miles.

The entire city’s layout gave off an impression that its original builders, whoever they were, planned the city in an unprecedented way, something that allowed the construction of a city worthy of gods.

But as impressive as the city is above the surface, it certainly is equally stunning beneath the surface.

There, beneath the massive pyramids that made Teotihuacan famous in the world are numerous cavities, chambers, and tunnels running for miles out. Beneath the foundations of the ancient city is a massively interconnected labyrinth.

Numerous tunnels exist underneath Teotihuacan’s pyramids. Inside them, researchers discovered hidden tunnels and cavities that were, supposedly, meant to illustrate the underworld.

Some of these tunnels were discovered thanks to an electrical resistivity study done by researchers from the National Institute of Anthropology and History, joined by scientists from the National Autonomous University of Mexico (UNAM).

The tunnels, however, are not a new discovery, and certainly not a surprising one.

The existence of a vast and mysterious underworld composed of caves and man-made tunnels beneath Teotihuacan and its pyramids is an untold secret that has been known for centuries.

Similar to the pyramids of Giza and their subterranean world, the tunnels, cavities, and chambers beneath Teotihuacan are said to connect the most critical sections of the city by underground networks.

One of the first documented cases of subterranean tunnels and chambers beneath Teotihuacan was recorded by the French explorer and anthropologist Desiré Charnay.

Charnay was one of the first Europeans to enter the vast labyrinth of tunnels in modern times and pen down a detailed account of it.

The French researcher recounts in his 1880 book “Les anciennes villes du Nouveau Monde,” being led by a local guide into strange cavernous quarries, located approximately two-and-a-half miles (around 1.6 kilometers) west of the Pyramid of the Moon at Teotihuacan.

The underground world of Teotihuacan is a big one. It is so big that geologists argue that some of the cavities that exist beneath the ancient city may have originated millions of years ago, due to the intense volcanic activity of the area, which created a natural network of lava tubes.

The builders of the city knew of their existence and even expanded some of the cavities, turning them into large chambers. Smaller tunnels were ‘reconstructed,’ and the ancients developed them as well, removing millions of tons of volcanic rocks, that were later used to build some of the buildings in Teotihuacan.

This feat alone is beyond impressive. The ancient city of Teotihuacan was built long before the Aztecs ruled Central Mexico. When the ancient Aztecs ‘re-discovered Teotihuacan, the city was already ancient to them, and was in ruins, covered by vegetation.

This means that long before the Aztecs, the ancient Teotihuacan culture excavated millions of tons of volcanic rock.

Revealing Teotihuacan’s secrets

During the 1950s-1960s, archaeologist Rene Millon, together with George L. Cowgill, systematically mapped the city of Teotihuacán in the Valley of Mexico.

Millon speculated that Teotihuacan’s largest pyramids were built beneath massive networks of subterranean chambers and cavities.

During excavations near the Pyramid of the Sun–the largest Pyramid at Teotihuacan–Millon discovered traces of what seemed to be a massive blocked pit.

Millon argued that the pit led towards a tomb of massive proportions. Despite his exciting find, in 1971 it was revealed that the pit leads not to the entrance to a massive tomb, but into a vast ancient network of tunnels beneath the Pyramid.

Following a tunnel running beneath the pyramid for around 100 meters, just at the center of the pyramid were a series of ancient chambers.

The archaeologists discovered traces of the tunnel being blocked off in ancient times.

Nonetheless, the chambers that the tunnels led to yielded only smaller figures made of obsidian, as well as pottery fragments, indicators that the tunnels, as well as its chambers, may have been looted in antiquity.

Despite this, Teotihuacan had more to offer. Perhaps more than archaeologists thought possible.

Further studies

Comprehensive studies and examinations of the caves and chambers in the 1990s, led by UNAM researcher Linda Manzanilla to conclude that the complex network of tunnels, cavities, and chambers beneath Teotihuacan were not lava tubes, but man-made structure beneath the surface.

Manzanilla argued that the chambers were probably used as subterranean qualities in ancient times which were then reused for funerary and/or ritualistic purposes.

Archaeological excavations in 2006 revealed another of Teotihuacan’s ancient secrets.

A group of experts found a nearly 60-foot vertical shaft located beneath Teotihuacan’s Avenue of the Dead.

Excavations revealed a fascinating network of tunnels and chambers. Inside, the archaeologists recovered human rains as well as many artifacts crafted from obsidian. The exact purpose of the tunnels and chambers beneath the avenue continues to elude experts.

In 2017, using electrical resistivity imaging, a group of scientists mapped the composition of the chambers beneath the avenue of the dead, revealing larger subterranean cavities as well as the presence of groundwater.

At a depth of around 26 feet, and starting at the center of the avenue, the scientists found there was a massive cavity at 49 feet, leading towards another larger chamber located beneath Teotihuacan’s Pyramid of the Moon.

The more experts explored, the more fascinating details were revealed.

Although the age of the tunnels remains an enigma, the experts discovered that the walls of the excavated tunnels were decorated with pyrite. The walls of the tunnels were covered in pyrite powder, a mineral that reflects the light and shines in the dark.

It is believed that this complex network of underground tunnels may have served in ancient times as a symbolic gateway connecting the ancient underground world with the sky.

These tunnels were sealed off around 300 CE for reasons unknown.

Purpose

But what led the ancient builders of Teotihuacan to put such an effort in creating a massive subterranean world, with extensive tunnels and chambers?

The effort is even more significant when you realize that they also managed to build one of the largest ancient cities in antiquity, with massive temples, pyramids, plazas, as well as housing units and markets.

For the ancient Teotihuacan culture, the underworld played an essential role in their belief system.

Therefore, it isn’t surprising to find a massive underground complex beneath the city.

Teotihuacan was of great importance, and its surface was reflected in the subterranean world.

Baffling discoveries

In 2003, archaeologists exploring the Pyramid of the Feathered serpent discovered a tunnel spanning hundreds of meters beneath the structure.

The opening was discovered by surprise by INAH archaeologist Sergio Gómez. As noted by the Smithsonian, in the fall of 2003, torrential rains swept through the ancient ruins of the “city of the Gods.”

The heavy rainfall would eventually reveal a massive sinkhole at the footsteps of the Pyramid. But little did Gómez know that the massive hole near the pyramid led to a secret kept for thousands of years.

Not knowing where the sinkhole led, the archaeologist descended into the darkness.

Once on the ground, he realized that he was standing in what appeared to be a massive, man-made tunnel. The ceiling of the tunnel was visible, although both ends were sealed off by massive boulders.

Whatever was sealed off thousands of years ago, was meant to remain sealed forever. That thought alone was enough to realize that the secrets inside the sealed chambers were of great importance.

In 2004, Gómez and dozens of other archaeologists scanned the area with ground-penetrating radar. Results of the scan revealed a massive tunnel going hundreds of meters into the center of the Pyramid of the Plumed serpent.

The sinkhole that opened up in 2003 was not the actual entrance, but a part of the tunnel that was weaker than the rest.

The sinkhole would eventually reveal one of the most fascinating discoveries of Teotihuacan.

With the help of remotely controlled vehicles, workforce, and a lot of patience, archaeologists discovered three chambers past the sealed off parts of the tunnels.

Inside, archaeologists found countless artifacts including intricately carved jade statues, the remains of cats, jaguars, as well as spheres.

But in addition to that, the archaeologists found traces of liquid mercury beneath the pyramid. This was a huge discovery, hinting at the possible existence of royal burial chambers.

As noted by Gómez, the liquid mercury was most likely deposited there thousands of years ago and served as a representation of an underworld river.

Speaking to Reuters in 2015, Gomez explained: “The Tunnel is the metaphorical representation of the conception of the underworld.”

The builder of Teotihuacan most likely created liquid mercury by heating mercury ore. Liquid mercury was used to decorating a number of objects as well as the bodies of the royalty.

This was not the first time mercury was found in ancient Mesoamerican sites. Previously, archaeologists found traces of mercury at two Maya and one Olmec site.

However, the amount of liquid mercury found beneath the Pyramid of the Feathered Serpent is far larger than in any other site.

It has been argued that pyrite powder in combination with liquid mercury was used by the ancients to recreate the mythical underworld, and the chambers and tunnels were most likely used for ritual purposes.

Inside the tunnels located beneath the Pyramid of the Feathered Serpent, the archaeologists also discovered thousands of spheres covered in pyrite powder.

In 2018, excavations beneath Teotihuacan’s Pyramid of the Moon revealed another chamber and underground tunnels.

These too were thought to have been used in ancient times for various rituals deeply connected to the underworld.

The chamber was found to measure 15-meters in diameter. The tunnel leads towards the Plaza de la Luna, 8 meters beneath Teotihuacan’s second-largest Pyramid.

The find of 2018 follows a series of previous discoveries, some of which date back to the 1980s when archaeologists Rubén Cabrera and Saburo Sugiyama recovered skeletons of elongated skulls, as well as obsidian statues, necklaces and intricately carved anthropomorphic figurines in tunnels located under the pyramid.

Even though no burial chamber was found beneath the pyramid, archaeologists say that the discovery itself reinforces the idea that the numerous tunnels, chambers, and cavities were used in ancient times for ritual purposes.

What secrets will Teotihuacan reveal in the near future? We can only wait and see as experts continue exploring and excavating one of the largest, and most populated cities of antiquity.

Stay tuned for more, and follow me on Twitter for updates on Pyamidomania, a World of Pyramids.