Slickrock logo

Belize’s Actun Tunichil Muknal Cave

By Slickrock Adventures on January 22, 2020

Written by Luna Wasson


In March of 2019, as I was wrapping up two months of working with Slickrock on Long Caye at Glover’s Reef, I had the opportunity to take a tour of Belize’s Actun Tunichil Muknal (ATM) Cave, also known as “Cave of the Crystal Sepulcher”. Located in central Belize near the town of San Ignacio in the Cayo District, ATM Cave is considered the ultimate Belize cave to visit, and for good reason. It features lush jungle hiking, river crossings, cavernous limestone chambers and sparkling mineral formations, Mayan artifacts and remains, some swimming and gentle climbing, and a captivating glimpse into the story of the Mayan civilization.


My previous caving experience was limited. I’m usually drawn to activities that get me to a summit or viewpoint, the sunnier the better. Several years ago, three friends and I spent six hours navigating the impossibly small tunnels of a cave in eastern Idaho, trying to find the path that connected to an adjacent cave with only a small hand drawn map as reference. This cave is in the mountains and holds ice year-round, so despite us visiting in mid-August, we were bundled from head to toe in warm layers. Looking back, I have a strong appreciation for that adventure, but it’s not one that I need to revisit just yet.




The prospect of ATM Cave sounded much more appealing. For starters, it can be visited comfortably in shorts and a t-shirt, thanks to the tropical climate. Expert guides know exactly where you’re going the entire time, and at no point are you required to squeeze yourself between the ceiling and floor of the cave for multiple yards. Having studied geology in college, I’m a huge fan of rocks and their formation histories, and limestone caves like ATM are prime examples of places where you can see the process of how a formation came to be.

Our expedition began in the early morning, boarding a bus in San Ignacio, and driving an hour out of town and into the jungle. We rode past open fields of cleared land, tree farms, and dense forest as the dirt road wound further into the hills, leading into the Tapir Mountain Nature Reserve. After unloading, our guide made sure everyone had the essential items, and nothing more. For this tour, each of us was equipped with a climbing-style helmet and caving headlight, sturdy hiking shoes, socks, clothing we could hike and swim in, and a water bottle. As of 2012, cameras are not allowed inside ATM Cave, following too many incidents of visitors dropping cameras onto Mayan artifacts while trying to photograph them. Our guide emphasized the upside of being empty handed on this outing—when we don’t have the option to bring along bags and cameras and extra items, we can focus on our surroundings and take in the experience. I was initially disappointed to not be able to photograph my experience, but later appreciated not having to worry about keeping track of a camera, and I’m doubtful my photos would have turned out well in the incredibly dark cave.



We began our 45-minute walk through the jungle, encountering three stream crossings ranging from chest to ankle deep. In a clearing before the cave entrance, we took a final bathroom and water break before stashing our water bottles. Our guide outlined our journey through the cave, and explained to us how important it is for us as visitors to minimize our impact on the cave environment. ATM Cave sees many tour groups each day, especially during peak season, and the cave environment is fragile. It was recommended to wear long sleeves instead of sunscreen and bug spray, as these chemicals would immediately wash off as soon as we began swimming. We were also instructed to be careful of our hand and foot placements, as oils from our skin can damage the rock crystal formation, and visitors must take extreme care when walking among the Mayan artifacts.

While ATM Cave is a popular place, our guide timed our entrance into the cave to give our group space and create a feeling of solitude. Though I knew there were groups ahead of and behind us, it felt like we were the only ones there for most of the tour.

Entering the cave was our first commitment to the adventure. We pushed off from boulders on the edge of the stream, and swam across a deep, turquoise colored pool of water to reach a limestone ledge. There, we turned on our lights for the first time, and descended into the darkness of the cave. The route consisted of walking through a shallow stream, portions of wet limestone, and deeper pools that required a short swim. My headlight beam illuminated huge ceilings hanging above us, covered with folded and rippling speleothem clusters, glittering calcite crystals, lumpy pillars and towers of stalagmites. We moved through the pools and shallower creek beds, over sharp and smooth limestone with polished corners, worn down by the flow of water, and walked over river pebbles. We caught glimpses of bats flying above, and even spotted one clinging to the limestone wall, and a few fish and small crustaceans could be seen in the water.






We reached a large boulder that provided a route up to the ledge above, where we removed our shoes and proceeded in sock-covered feet. Wearing just your socks keeps oils from your skin off of the cave, and makes you slow down a little and take more care with each step. This area is where the Mayan artifacts began, and the only separation between the ancient remains and us was stretches of orange tape on the ground. We began to see countless fractured pots, partial skeletons, and carved speleothems. Our guide began to dive in to what became my favorite part of the tour—the story of what we know about the Maya and the artifacts they left behind.

The Maya revered the cave as a place of worship and sacrifice, and archaeological dating of items found in the cave align their activity with the decline of their civilization during an ongoing and worsening drought, between 700 and 900 AD. Guided only by torchlight, they were bringing in many large clay fired coil pots for ceremonial purposes. As we continued upwards through the cave passage, we saw remains of human sacrifice, thought to be associated with growing desperation for water and attempting to appease the gods of fertility and rain, whom the Mayans believed resided there. Springs and ground water flow into the cave, and if these were drying up, one would have to proceed further and further into the cave to reach water, a story line that matches up with the dated artifacts.






Our guide pointed out several different stalagmite and stalactite features that were carved to display shadow patterns when a light was shone against them. One we saw outlined the profile of a man’s face, and another looked like three figures paddling a boat together. When we lined up our headlights just right and moved them with specific instruction from our guide, it gave the illusion that the figures in the boat were actually moving their paddles. From any other angle, it would just appear as another rock, but with our guide’s keen eye, we were able to see interior of the cave as it might have appeared to the Mayans.

After making our way through a giant chamber known as “the Cathedral” and up and over more boulders using a ladder, we arrived at the end of the cave system, at least for our journey. If you’ve seen photos of ATM Cave, you’ve probably seen one of “The Crystal Maiden”, a striking skeleton calcified to the cave floor, glittering with mineral deposits. Originally thought to be a female skeleton, it was given the name “The Crystal Maiden”; more recent assessments have identified the skeleton as young male. The remains sit on the floor of a small chamber, beyond which the cave constricts to a small tunnel, too small for us to continue. As I observed the details of the skeleton, decayed but simultaneously preserved by the cave environment, our guide filled us in on the archaeologist’s findings—two crushed vertebrae, evidence for a violent cause of death.





We stood and observed, in awe of the structural beauty of the cave, and of the history told by what has been preserved. Our guide brought our attention back to the present, leading us back the way we had come to make room for the next group eager to reach “The Crystal Maiden”. We had reached the end of the cave, but our tour was only halfway complete, as we still had to make it back to the cave entrance.

The return journey proved no less exciting than the way in, even as we were retracing our steps. I felt more observant after adjusting to the beam of my headlight, and was able to notice more beautiful rock formations and glittering mineral crystals that I had missed the first time. On our way out, we took a different route than the one we had entered on, which meant sliding our bodies between two limestone slabs as the cool stream water rushed beneath us. Our guide instructed us to turn our heads at just the right time as we lowered ourselves, so we would fit between the rocks.





We reached a calm part of the cave, where the lights of the next group were out of sight. Our guide told everyone to turn off our headlights, just for a moment. It was instantly so dark that opening and closing your eyes made no difference. The darkness was so solid and complete, with no hint of light from any direction, that our guide informed us that our eyes would never be able to adjust.

After turning on our lights again, we continued out of the cave, eventually rounding a final turn where daylight became visible for the first time in several hours. As we approached the mouth of the cave, the light filled in around us, and I no longer relied on the beam of light from my headlamp to see. It felt as though we’d taken a brief trip to the underworld and we were finally returning.

Slickrock Belize Adventures is returning to ATM Cave this season as part of our Adventure Week trip, and I highly recommend it. There is no other experience like it, and we are incredibly lucky to be able to offer and share this adventure.


Photos for this blog are from our Guest Photos archive, courtesy of Brad Lantz and Dan Seagull. Photos were taken before the restriction on camera use in the cave was introduced.