The Filipino Outdoorsmen Who Map the Dark, Mysterious World of Caves

IMAGE Matty Adame/Unsplash

“The great mountains have been climbed, the vast deserts crossed, long rivers run. Every corner of the planet has been mapped and analyzed, studied by satellite. As the global community shrinks, any explorer who would be the first to set foot on unknown land is left with three choices: fly into space, descend to the ocean floor, or go caving.” So begins Gaia Exploration Club founder Mark Dia’s presentation on caving adventure travel

Gaia is a group of adventurers who aren't just into the regular outdoor sports—they also do what explorers have done since time immemorial: venture into the unknown and come back with maps. Moreover, they wanted to explore and map the dark, claustrophobic, primal spaces that are caves.

On its crystal walls were written in faint charcoal marks, “Viva La Independencia Filipinas." It was said that Bonifacio himself etched out those words.

A large upper chamber in the Lumiang-Sumaguing cave system

In 1989, Dia was an outdoorsman who would often go rock climbing in Montalban, and would take shelter under the rocks when the sun got too hot. One day, he and his friends found a cave and explored it all the way to where they thought it ended.


Later on Dia learned that that cave was actually the legendary Pamitinan Cave, where Bernardo Carpio was said to dwell, and where Andres Bonifacio and eight other Katipuneros had initiated new members during the Holy Week of 1895. He returned to the cave and, armed with new knowledge from a transcript of the great-granddaughter of one of the Katipuneros, he found the squeeze passage leading to a grotto. On its crystal walls were written in faint charcoal marks, “Viva La Independencia Filipinas." It was said that Bonifacio himself etched out those words. “From that moment on I saw caves in a different light, and I was hooked,” Dia says.

Mark Dia (third from left) with the members of La Venta Geographic Exploration group after an exploratory survey of the Underground River in Palawan

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La Venta expedition team leader Tono de Vivo doing a traverse while exploring a new passage in Puerto Princesa Underground River, Palawan. May 2017.

Three years later, he joined Speleo Philippines, a major expedition with the Bristol Exploration Club of the UK and Filipino mountaineering groups. “I joined that and made a lot of lifelong friends. We explored many new caves [in Peñablanca, Cagayan and Rizal], and mapped many kilometers of new passages. We learned a lot and realized that the Philippines had huge potential,” Dia says. Once the expedition ended, its members formed their own exploration clubs in their respective provinces. In 1996, he established Gaia Exploration Club as a Manila-based geographic and exploration organization.

A stalactite formation in a newly explored cave passage in Peñablanca, Cagayan


Helictites in Peñablanca, Cagayan Valley

When asked why he loves cave mapping, Dia explains: “[It] allows you to share what a cave looks like to those who either need or want to see it—how a cave originates from one place, goes under visible ground features, and makes connections to things like springs, rivers and mountains. We have also been able to save whole mountains from destruction by proving that a cave system goes underneath it. By law, you cannot just destroy a cave.”

Gaia Exploration Club was able to prevent a cement company from destroying an area in Bulacan, because they had found an extension of a historical cave running beneath the company’s concession area. They also got a gold company to delay and eventually reconsider their expansion because of a cave system in Nueva Vizcaya.

Various calcite crystal formations inside the Underground River, Palawan

Unidentified scorpion-like species in Puerto Princesa Underground River, Palawan

But Dia’s favorite expedition is the one Gaia Exploration Club conducted last May, in which they mapped portions of the Underground River in Puerto Princesa, Palawan with Italian group La Venta Geographic Exploration and Palawan-based group La Karst.

“We have extended the cave to more than 35 kilometers now,” he says. “We have seen fantastic world-class geological formations in the Gaia Passage extensions in that cave. It was also quite difficult to get to the unmapped passages—it took us about 5 hours of swimming, hiking, rope work, and crawling going just one way. We had to sleep inside the cave several times so that we could continue the work.”

It goes without saying that cave exploration is no picnic—one has to be prepared for all kinds of challenging terrain, such as pits, rivers, and waterfalls. You might have to climb walls to reach alcoves or higher passages. “When you are surveying a cave you have to be focused, and your caving skills should be of the highest standard,” Dia adds.


Gaia Exploration Club members surveying a wet passage in Quezon province

Successfully surveying a cave takes a good amount of preparation and training. First, team members have to calibrate their instruments to make sure their readings will be accurate. These include a compass for taking directions, a clinometer for measuring vertical angles, tape for measuring distances, and waterproof paper and pencil for recording readings. Each member of the team should know their respective roles beforehand.

“At each survey station we sketch the features around us, then continue on until we either reach the turn around time, determine that it is no longer safe to continue, or run out of cave to survey,” Dia explains. “We then return to where we can put all of the data onto clean sheets of paper or on a computer and start the process of mapping the cave.”

Newly discovered crystal encrusted passage—the tape is to indicate where cavers should pass to minimize damage. May 2017.

Gaia Exploration Club members Alan Tan and Mark Dia calibrating digital survey gear in Sagada, Mountain Province

To become a cave surveyor and mapper, one has to undergo intensive training that can take half a year to several years, depending on one’s performance and the availability of the trainers. To be qualify as a surveyor, one has to prove that one has patience, endurance, and determination; is a team player; and knows how to calibrate, use, and care for the surveying instruments.


To be a cave mapper, one needs to know how to read survey data, be familiar with mapping software such as Therion, and “have a bit of artistic flair,” as Dia puts it.

If you’ve got what it takes, it could be well worth the effort. After all, how many people can say they’ve discovered new caves and saved them from destruction?

Gaia Exploration Club members doing a survey of Sumaguing Cave, Sagada, Mountain Province

Surveying Sumaguing Cave in Sagada, Mountain Province

Gaia Exploration Club and La Venta collecting biological specimens in Palawan. 2016.


Navigator Chamber, Puerto Princesa Underground River, Palawan

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Angelica Gutierrez
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