There's more than a tunnel hidden beneath Mexico's second largest pyramid. A survey using electrical resistance technology has not only confirmed the existence of a tunnel running out the southern end of the Teotihuacan's 140-foot-tall Pyramid of the Moon, but also uncovered a chamber connected to it, reports Fox News. Possibly used by the Toltec peoples for funerals and other rituals, the hidden room is 26 feet beneath the pre-Aztec pyramid 30 miles northeast of Mexico City and stretches some 50 feet across. Like the tunnel, however, it has yet to be explored.
As human remains, necklaces, and other apparent offerings were found inside the pyramid in the 1980s, "it is not difficult to think that something similar could be found in the subsoil," archaeologist Verónica Ortega says in a release, translated from Spanish, per Science Alert. It's also believed a second tunnel awaits discovery. Archaeologists think its entrance may lie to the east of the pyramid, and they began searching that area earlier this month. The tunnel system as a whole is likely tied to a belief in the underworld: Ortega previously noted the discovery of funerary items would show the pyramid functioned, at least in part, "to emulate the underworld." (Tunnels beneath a Mayan pyramid served a different purpose.)