The mysterious underground network of Aztec pyramids

The secrets of the underground network that lies beneath the ''Avenue of the dead'' in the ancient city of Teotihuacan are gradually revealed.

The city of Teotihuacan is located about 30 miles northeast of Mexico City. Its name can be translated as "birthplace of the gods" or "place where gods were born." Even if it existed at least 300 years before, the city thrived during the Aztec civilization period as a religious and cultural center. 

The main feature of Teotihuacan is the "Avenue of the Dead", a road with a length of about 2.5 km, beginning at the Moon Plaza to the north and extending beyond the Ciudadela and the Great Compound complexes to the south. The site is surrounded by pyramids and platforms. The higher building is the pyramid of the Sun (216 ft), however, the pyramid of the Moon (200ft) appears to be taller as it was built on elevated ground.

Apart from the large infrastructure on top of the ground, it was clear that a developed underground network existed beneath the city. Back in 2003, archaeologists discovered a 60-ft vertical shaft under the Avenue. The investigation revealed a whole network of chambers and tunnels filled with human remains and objects made by green obsidian, a volcanic rock that was utilized during religious ceremonies.

Even if scientists expect that the underground network extents in the same pattern as the streets of the city, its size has not been determined yet. In 2017, a team of geologists mapped the underground area beneath the city by using electrical resistivity imaging. It was found that a large cavity under the Pyramid of the Moon is connected with a tunnel to the center of the avenue.

Pyrite powder covers the walls of the tunnels and chambers, a mineral that reflects the light and shines in the dark. Scientists suggest that the underground network acted as a symbolic gateway that connected the sky with the underworld. Until now, the age of this network remains unknown.