Text and Photography by Curt Bowen
For several years, Mexico's Caribbean coastline, south of Playa Del Carmen, has been considered by many to be the new frontier for cave exploration. Some of the world's largest underwater caves with surveyed passages of over 200,000 feet (60 miles) can be found there. The topography and geology of Mexico changes vastly once leaving the coastline and entering the interior of Mexico. Caves are no longer small to medium-sized shallow passages stretching over long distances, but rather, giant sinkhole type pits that drop deeply into the Earth.

Advanced Diver Magazine's staff member, Jim Rozzi, questioned Tony DeRosa, during a previous cave diving trip to Villa DeRosa's, about any deeper systems that may lie further inland. Tony introduced Jim to Hilario Hiler, who has lived and breathed the Mayan culture for the last 32 years. Fluent in Spanish, English, and Mayan, Hilario has escorted many cave explorers, photographers, and archeologist throughout the Quintana Roo and Yucatan peninsulas in search of new discoveries. Jim quickly hired Hilario for a quick pre-exploration look into Mexico's deeper interior and its hidden secrets.
Hanging from the cave ceiling, vampire bats await the darkness of night to feed. Blood-stained vampire puncture wounds can be seen on the cattles' backs every morning.
After returning from Mexico, Jim contacted me to describe his findings. He described places of immense beauty, Mayan folklore, and hundreds of previously unexplored cave systems awaiting discovery. Full of enthusiasm, Jim began the immense task of organizing a large expedition to these remote, unexplored locations. Tanks, oxygen, helium, dive gear, video cameras, photography equipment and climbing /repelling equipment all needed to be gathered, filled, transported, analyzed, and setup.

Jim contacted Tony DeRosa again and organized access to over sixty scuba cylinders, sixteen sets of doubles, four large helium bank cylinders, and four large oxygen cylinders. A large van was also provided to transport divers and personal dive/photography equipment. Additionally, a large flat bed truck was secured to transport the large amounts of scuba cylinders into the Mexican interior.

Jim arrived at Villa DeRosa two days prior to my arrival to organize, mix cylinders with trimix and decompression gases for expected depths of up to 400 ft /122m. Joining us on the dive were Hilario Hilar, as a personal guide and translator; Gonzolo Vaccalluzzo, as a safety diver and explorer; Montano, as the van driver and equipment guard; and Linda Bowen as a surface photographer. By the time I arrived, all the work had been completed; there was nothing left to do but dive.

As we maneuvered into the Northwest of Mexico’s Yucatan, the transition was made from that of the coastal tourist to that of a jungle denizen. The Mayans who dwelled in these remote locations, although quite poor, were rich in spirit, always eager to assist us.

Far Left: Project coordinator Jim Rozzi prepares to be lowered into cenote Chi May for a quick exploratory look.

Left: Hanging just above the water's surface makes for an excellent vantage point for cavern zone photography
Above: Tree roots snake their way down to the water's surface of Cenote Chi May. Once having reached the water, the roots spread out, creating large root islands that sometimes reach a depth of over 40 feet.

Below: Displayed is an artist's rendition of the Cenote Chi May. Exploration reveals a debris cone starting at 170ft./52m. and sloping down to an undetermined depth. Maximum depth explored was 245ft./75m.
Left: Cenote UCIL was originally explored by Sheck Exley, Paul Deloach, and Hilario Hiler in 1989, and then later explored by Andreas Matthes to a maximum depth of 385ft./118m. ADM divers, Jim Rozzi and Curt Bowen, explored the opposite side of the sink to a maximum depth of 345ft./105m.

“World Class Diving” Sheck Exley.

Right: A small cave entrance allows easy access to the beautiful cavern zone and the deep cobalt blue waters of Cenote UCIL.
One of the most challenging obstacles these pits provide, besides the extreme depths, is difficulty in accessing the water since they typically have a 30 to 50 foot straight vertical drop to the water level. The only way to gain access is to either repel or be lowered into the pits by ropes and pulleys. Being the very first person ever to explore the depths of any untouched cave is of itself extremely thrilling. Prior to this expedition, only one system out of a dozen had been before explored. On most systems, it was difficult enough lowering doubles, stage cylinders, and divers totally equipped for deep exploration into a deep pit. However, for most dives, we chose to lower a single diver with aluminum 80 to do a quick exploration check to get a better idea as to the cave configuration. This procedure saved time and needed gas for the systems that actually went deep.

After determining the potential of the cave, the deep divers were lowered into the water, followed by their equipment. Floating around on the surface they would gear up, perform an S drill, tie off their cave reel, and descend into the depths. As each diver descends, his decompression cylinders are lowered on pre-measured ropes into the water and down to their designated depths. Later, as the diver ascents, he retrieves his stage cylinders and completes the required decompression stops. Upon returning to the surface, the diver would complete a short surface decompression, then prepare for the cylinders to be hoisted from the pit by a rope master and several Mayan sherpas. After all the cylinders have been retrieved, the difficult task of retrieving the divers follows. A harness is lowered on a 2-1 mechanical advantage pulley system for the diver to strap on. Once tightly into the harness, the verbal command to hoist the diver out of the water is given, and the grunting and groaning begins until the diver is hauled to the surface.
Native to the area, large iguanas can be seen sunning themselves along the jungle paths and roadways.
Left: In Libre Union, local Maya boys watch cartographer, Curt Bowen sketch the unfolding of the mysteries of the Cenote.

Cenote Chi May

One of the most beautiful cenotes of the exploration project was located beside the main road, just outside of the village of Libre Union, called Chi May. As illustrated on the far-left page, Jim and Gonzolo explored this system down to a depth of 245 ft./75m. During the descent the white walls were seen covered with beautiful stalagmite formations to a depth of around 150 ft./46m.
The top of a tallis cone was encountered at 180 ft./55m and a heavy halocline at 200 ft./61m. Dropping deeper in hopes of making it through the hydrogen sulfide gas layer, they dropped to a depth of 245 feet. With the decreased visibility and the hydrogen gas layer making their lips numb, Jim turned the dive. It appeared that the silt mound continued down at a 45-degree angle and the nearest wall was at least 70 feet away. An estimated maximum depth of the cenote could be around 300 ft./92m.
This Red Kneed Tarantula, common to the area, can be found lurking around the jungle. One should check sleeping bags before turning in, in the evening and check their boots in the mornings. Tarantulas also like wet suits and diving booties!
First explored in the late 80's by Sheck Exley, Paul Deloach and Halario Hiler, this cenote is a must see for any visiting cave diver. Just the dry cavern zone's beauty alone is worth the time and effort (see page 33). A small cave entrance leads down through an impressive cavern zone to the mineral cobalt blue waters of Ucil. Descending into the cenote, the white walls quickly widen to over 200 ft./61m across. At a depth of 300 ft./91m, we discovered the top of the tallis cone. Tying off to a tree branch on the top tallis cone, we descended down the rocky cone to a depth of 345 ft./105m, where the floor levels out and we encounter the wall. The opposite side of the system was pushed to 375 ft./114m by Sheck Exley and then later by Andreas Matthes to a maximum depth of 385 ft./117m.

Cenote Libre Union (Illustration above)

Located in the middle of the village Libre Union is a unique cenote where the village draws their water. Hundreds of Mot Mot Birds fill the air as the fly in and out of the cenote's cavern zone. The Mayans have built a wall around the cenote to prevent any accidents from occurring. According to Mayan rumor, they believed that this cenote was connected to another cave located on the other side of the village.

During the Expedition Dzonote Maya, many unexplored cave systems were discovered as well as Cenotes that didn't pan out. Yet, each one had its own unique beauty and discoveries. Linda Bowen poses as the sun's light rays produce a magical view of this cave the Mayans call Muulchen (mound of the well). Only a small shallow pool of water lies in the bottom of the cave.
I geared up and was lowered into this cenote for an exploration dive. Looking down on the water's surface, I could faintly see the top of the tallis cone. Tying off my cave reel to the well pipe, I descended to the top of the tallis cone at a depth of 117 ft. Re-tying to a tree branch, I headed down over the cone and the far wall came into sight. With visibility of over 100 feet, exploration was easy and I had reached a maximum depth of 152 feet. Tying off again at the wall, I made a sharp left turn and followed the wall all the way around the sink until I had returned to my line. At no time did I see any passage that appeared to continue off from the cavern zone. Due to over one hundred years of human involvement this system, it had collected lots of discarded trash. Later on some of us tried to explain to the local Mayans how throwing trash into this cenote was detrimental to their health and their clean drinking water. As we were leaving we noticed the local school teacher had all the kids out picking up all the trash from around the cenote.

Although not all of the cave systems we discovered were deep (several were only 30-60 feet), each had its unique beauty and offered the opportunity of discovery, making this expedition truly an adventure. In fact, it was one of the best I have ever experienced.
This unique, colorful, and very noisy bird called the Mot Mot Bird builds its nest in the walls and ceilings of the Cenote's cavern zone. On any dive, hundreds of these birds fly in and out of the Cenote's entrance as they gather their daily food.
Left to right:
Curt Bowen, Linda Bowen, Gonzalo Vaccalluzza Montano, Jim Rozzi, Filemon Lopez, Irvin Valente, Halario Hiler, Felipe Aqvilar