Another day, another secret tunnel beneath another Mesoamerican temple. We’re not unimpressed – it’s just that it seems to us that these ancient structures seem fairly capable of hiding a lot of enigmatic passageways.

Now, as first reported by El Universal, the latest discovery involves Kukulcan Temple, an edifice that was built by the pre-Columbian Maya civilization. It’s already been known that plenty of underwater caverns exist beneath this 30-meter-high (98-foot) monument, but a new passageway has been uncovered, one that could lead to a subterranean sinkhole, also known as a “cenote”.

As is normally the case with these things, the cenote wasn’t initially excavated or explored directly; it was found using a type of X-ray-based imaging two years ago by a team at the National Autonomous University of Mexico (UNAM). Now, a team led by the Great Mayan Aquifer Project has found the entrance to the cenote within the ossuary room, which is where the bones of the deceased were once placed.

Through the ossuary, the researchers made their way some distance into a secret tunnel before coming across a blocked entrance. It’s likely that the blockage was caused by the Mayans themselves, and it’s possible that clearing it would reveal a path to the as-of-yet unseen underwater aquatic reservoir.

The temple itself is covered in feathered serpents, a tribute to Kukulcan, a Mayan snake god closely related to several deities found in several other Mesoamerican religious systems. He’s been associated with war, and his name is shared with an individual who may have been a ruler or priest in the region around the 10th century.

This particular god doesn’t seem particularly friendly. He’s seen in carvings overseeing human sacrifices, which appeared to be a central feature of a cult that sprung up in his name. Is this new tunnel related to this cult in some way? It’s likely, but we can’t say for sure at this point.

At present, plenty about the site, and in particular what lies beneath it, remains a mystery. So, while the passageway is being dealt with, an international group of researchers are hoping to produce a 3D map of the labyrinth beneath the entire Chichen Itza archaeological site, which itself dates back to the 7th century.

El Castillo, as the Spanish referred to it, is undoubtedly built atop a rather dramatic landscape. Forget the cenotes for a second, and consider that it’s found on the same peninsula that was ground zero for the end of the age of the dinosaurs. It’s a site of stunning archaeology and geology, one that continues to baffle researchers to this day.