The hourglass-shaped entrance to Actun Tunichil Muknal, “The Cave of the Crystal Sepulchre,” in Belize.
The ancient Maya believed caves were portals to the underworld, which they called Xibalba.
Some parts of the cave are only accessible by climbing — a challenging task even with modern equipment.
The Maya ventured into these caves — in some cases traveling more than a mile underground, swimming down subterranean rivers, climbing precipitous cliffs or lowering themselves into tight hollows.
Archaeologists can only access some of these places with ropes.
Archaeologist Holley Moyes wades through the high waters of Actun Tunichil Muknal to reach artifact-laden chambers within its depths.
A 1,000-year-old skull, above, offers evidence of subterranean sacrificial rituals. In dark crevices of the central chamber, Moyes and her colleagues counted 14 human skeletons, some tucked away in corners, others splayed out in the open.
Following in the Maya’s footsteps, archaeologist Mark Robinson paddles through chest-high waters just inside the cave entrance.
Ancient Maya may have traveled deep into these caves to conduct ritualistic sacrifices to Chac, the god of rain.
Actun Tunichil Muknal is a giant limestone cave in the jungle of western Belize. Over the past 50 years, archaeologists have discovered vestiges of religious rituals in hundreds of caves throughout the land of the Maya.
In Actun Tunichil Muknal, or "Cave of the Crystal Sepulchre," the remains of a 20-year-old woman known as the "Crystal Maiden" have laid for more than 1,000 years. Archaeologists believe she was sacrificed by a priest as part of a religious ritual.
Archaeologist Holley Moyes has spent two decades crawling into jungle-choked caves to answer one question: What drove the Maya to make offerings in such dark, remote places?
Read the full story of the Cave of the Crystal Maiden on Discover.
Archaeologist Jaime Awe threads tight passages, neck-deep water and almost total darkness to reach ritual sites deep within Actun Tunichil Muknal.
Moyes examines an ancient ceramic vase in one of the cave’s many chambers. Most artifacts discovered closer to the entrance of the cave dated from A.D. 250 all the way up to the ninth century A.D. However, deep in the darkness of the main chamber, the artifacts all dated from the eighth and ninth century A.D.
Then, as abruptly as they began, the ceremonies ended. There was no sign of the Maya in the caves beyond the middle of the ninth century A.D.
For more than 1,000 years, the calcite-encrusted skeleton of a 20-year-old Maya woman called the Crystal Maiden has lain where she fell in a chamber deep within Actun Tunichil Muknal. Archaeologists believe she was sacrificed to appease Maya deities as populations plummeted.
Stalagmites rise to meet stalactites in Actun Tunichil Muknal’s main chamber.
Moyes leads the way through one of Actun Tunichil Muknal’s perilous passageways.
In 1997, Moyes joined a team that conducted the first in-depth study of the cave. Each day she swam through the mouth of the cave. During long hours underground, Moyes helped map the cave and scour the floor for traces of the Maya.