Actun Tunichil Muknal (Cave of the Crystal Sepulchre), Belize

A well-preserved skull in the ATM Cave, Belize

photography by: Antti T. Nissinen/ Flickr

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Deep within the dense rainforests of Belize lies a spiritual site, whose gruesome content now offers a glimpse into the mysterious rituals of the Maya Civilization, which dominated the area for centuries. Actun Tunichil Muknal or simply ATM, is a secluded system of caves where the skeletal remains of sacrifice victims are frozen in time, telling the forgotten story of a once mighty empire.

For more than a millennium, a remote subterranean world awash with a treasure trove of Mayan history was entirely cut off from the rest of the globe. After its discovery in 1989 and opening to the public in 1998, though, Actun Tunichil Muknal (also known by its whimsical initials – ATM) quickly became a top destination for intrepid travelers, for whom visiting the inaccessible site has been deemed the ultimate adventure.


Ensconced within the Tapir Mountain Nature Reserve in central Belize, this mid-jungle cave once served as a sacrificial place by the Mayans. It was here where the lives of infants, children, juveniles and adults were offered as gifts of appeasement to the Mayan Gods.


It is believed that most of those who were killed here, sustained cranial injuries, some of which even ended with their skull cracked wide open. While the cave was first explored somewhere around 300AD, it wasn’t until 700AD to 900AD, when it was actually used as a place of worship, where the sinister rites were performed.


Eerily strewn throughout the dark labyrinth are 14 unearthed skeletons of sacrifice victims, serving as a silent testimony for their owners’ brutal death. Across the years, the mineral-rich water within the underground chambers seeped into the bones of the deceased, resulting in their calcification. This natural process affixed the fossilized remains to the cave floor, and also imbued them with a dash of glossiness.


Standing out among ATM’s more than 1,400 human artifacts is a single skeleton by the name of “Crystal Maiden”, located in a chamber known as the “Cathedral”. As its moniker suggests, the well-preserved relic was originally classified as a young female. It was only later determined that the skeleton actually belongs to a 17-year-old boy whose death was exceptionally violent, as evident by the smashed parts of his spinal column.


Like the rest of his long-dead counterparts, the Crystal Maiden, or Crystal Prince as he is referred to by some, most likely ended his life as a human sacrifice. Interestingly, due to their high content of calcium, the bones glitter upon exposure to a flashlight, hence his apt name.


Surrounding the skeletons are copious ceramic shards and pots, purportedly used to capture the spirts of sacrificed victims. The souls were then released by tossing the urns onto the ground and breaking them apart, or as other artifacts indicate, puncturing the pots with “kill holes”, from where the imprisoned spirit could escape.


Somewhat surprisingly, alongside the dead are also a slew of living critters, including various species of fish, bats, crabs and perhaps most notably, Amblypygi (aka whip spiders), a type of a cave-dwelling arthropod that lacks venom-injecting fangs and silk glands.


Whoever wishes to visit this well-hidden gem will have to go to great lengths (literally so), as ATM’s remote whereabouts make it exceedingly inaccessible. To protect the delicate site, there is a limit of 125 visitors per day, all of whom can explore the dark maze solely with a licensed guide. Tours often depart from San Ignacio and include a 45-minute trek through the jungles, where visitors will have to wade their way through a series of streams before reaching the mouth of the ATM Cave, the first segment of which entails another extremely wet hike along an underground river.


Take note that due to past accidents involving tourists damaging the place’s skeletal remains, neither cameras, nor footwear are allowed within the confines of the cave.