'Gateway to the underworld' beneath ancient Mexican pyramid hints at advanced civilization
An often overlooked ancient pyramid in Mexico was filled with pools of a rare element in its underground chambers, leading to new theories that the structure may have had a shocking hidden purpose.
Mexico's Temple of Quetzalcoatl, or the Feathered Serpent Pyramid, in the ancient city of Teotihuacan is believed to have been built between 1,800 and 1,900 years ago.
The mysterious structure is shrouded in conspiracies ranging from being an ancient power plant to the engine for an extraterrestrial craft.
A discovery in 2015 suggested the ancient civilization at Teotihuacan used the temple to 'look into the supernatural world.'
Researcher found 'large quantities' of the rare and toxic liquid mercury in hidden chambers at the end of a 338-foot-long tunnel.
Liquid mercury shimmers and has reflective properties like water or a mirror. Water was seen as a portal to the divine or underworld, connecting the living to supernatural realms.
Mexican researcher Sergio Gómez believed the Teotihuacan civilization filled the chamber with pools of mercury to act like a gateway to the underworld for an unknown Mesoamerican ruler.
While the discovery took place a decade ago, it recently went viral online as social media users have again been captivated by the mystery.

Mexican archaeologist Sergio Gómez announced in 2015 that he found large amounts of liquid mercury in a chamber at the end of a tunnel (pictured) that had been sealed off for more than 1,800 years

Gómez led the excavation project, known as the Tlalocan Project, starting in 2003 after a sinkhole revealed the tunnel's entrance at the Feathered Serpent Pyramid (pictured)
There is another theory about this remarkable discovery at Teotihuacan, connecting the liquid mercury and another substance found at the site to advanced technology that was centuries ahead of its time.
Along with the pools of liquid mercury, researchers at the site also unearthed large sheets of mica, a shiny silicate mineral with insulating properties.
Although Gómez's team suggested at the time that these two materials were likely part of an elaborate ritual, more recent speculation has suggested that the liquid mercury and mica were actually key pieces of an energy-generating device inside the structure.
To date, archeologists have only found 'rivers' of liquid mercury in one other pyramid-like structure in the world - the Mausoleum of the First Qin Emperor in China - making its use in ancient structures baffling.
Meanwhile, scientists have been working to confirm whether Egypt's Great Pyramid of Giza was actually an ancient power plant after finding signs that the structure was capable of amplifying energy waves from space.
Those theories have only gained more momentum after researchers found evidence that a vast city could be sitting underneath the Giza pyramid.
To this point, expeditions throughout Mesoamerica had only found much smaller traces of liquid mercury at one Olmec and two Mayan sites.

Gómez and his team suggested at the time that this was likely all part of an elaborate ritual, marking the journey of an unknown Mesoamerican king into the underworld
Excavations in the early 1900s uncovered mica all around the city of Teotihuacan, with Gómez's team discovering even more lining the chambers of the nearby Pyramid of the Sun and within the tunnel under the Feathered Serpent Pyramid.
Annabeth Headrick, an art history professor at the University of Denver specializing in Mesoamerican cultures, said after the discovery: 'Mirrors were considered a way to look into the supernatural world, they were a way to divine what might happen in the future.'
'A lot of ritual objects were made reflective with mica,' Headrick told The Guardian in 2015.
What makes this discovery strange is the fact that one of the major sources of mica anywhere near Teotihuacan sits in Brazil, roughly 4,600 miles away.
Additionally, mercury doesn't exist in nature in its liquid form, meaning the ancient Mesoamericans had to use an extremely difficult and hazardous process to extract it from a rock called cinnabar - a light red stone made up of solid mercury sulfide.
Specifically, they would have needed to heat this stone until the mercury would begin to melt out and then somehow safely transport the highly toxic element to the pyramid tunnel without dying from exposure.
Gómez's team argued that the mercury and mica were part of a ritual marking the journey of an unknown Mesoamerican king into the underworld.
However, those who believe in the power-plant theory surrounding the Temple of Quetzalcoatl argue that archeologists have never identified who this ruler of Teotihuacan was and have not found a burial chamber anywhere in the ancient city.
The lack of a royal chamber has only fueled speculation that the mica and mercury were components of a mechanical energy device - built over 1,700 years before the first electrical power plant was invented.

Mexico's Temple of Quetzalcoatl, or the Feathered Serpent Pyramid, in the ancient city of Teotihuacan is believed to have been built between 1,800 and 1,900 years ago
Ancient astronaut theorists have gained a pop-culture following due to their unsupported theories suggesting that many ancient mysteries are evidence of early human contact with extraterrestrials.
Some fringe theories, including those made by ancient astronaut proponents, have suggested that liquid mercury's conductive properties may have helped power either an electromagnetic or propulsion device.
Other theories claimed the mercury pools in the tunnel may have been part of a closed-circuit system, generating electricity or electromagnetic fields when combined with other materials or structures.
Since mica is such a good insulator of heat and electricity, those fringe theories have suggested that the mineral was used to channel or contain energy within the pyramid and tunnel.
The sheets lining the tunnels and chambers under the pyramid would have created a 'capacitor-like' system, storing or directing energy.
However, researchers have not found any evidence to support these theories, other than the unusual presence of both materials inside the ancient structure.