The history of the Río Camuy Caves doesn't begin with humans, but much earlier, in the slow work of geology. All of northern Puerto Rico is formed by a thick strip of limestone, deposited tens of millions of years ago when this area was under the sea. Over time, that limestone bed emerged and was exposed to the tropical rain.
Rainwater, slightly acidic as it takes on carbon dioxide, began to dissolve the limestone, which is easily soluble. Over millions of years, that process created the karst landscape: mogotes (rounded hills), sinkholes (depressions where the water plunges) and, above all, a vast world of caves, galleries and underground rivers. The caverns' speleothems — stalactites, stalagmites and columns — are estimated to be about 45 million years old in their formation.
The main author of the Camuy system was the river of the same name, which on crossing the limestone strip plunged underground and bored through the rock, forming a colossal network of caverns. Thus, before any human presence, water and time had already sculpted one of the largest natural wonders in the Caribbean.
Long before modern scientific exploration, the Camuy River caves were already known and frequented by the Indigenous inhabitants of Puerto Rico. The archaeological evidence found in the system shows that the Taíno — and possibly earlier peoples — explored these caverns hundreds of years ago, leaving their mark in the karst's underground world.
For the Taíno, the caves had a deep meaning: they weren't just refuges or passing places, but spaces charged with spiritual and mythological meaning. In the Taíno worldview, caves occupied a central place in the origin stories, associated with the emergence of the sun, the moon and human beings. That's why rock art, petroglyphs and archaeological remains often appear in caves across the whole island.
This Indigenous presence connects the Río Camuy Caves with a whole world of archaeological sites in northern and central Puerto Rico, like the petroglyphs of the Cueva del Indio, in nearby Arecibo. Thus, the Camuy system is not only a geological wonder, but also a space with a long human history dating back to the island's native peoples.
The systematic, scientific exploration of the Camuy River cave system began in the mid-20th century. Although the system was officially 'discovered' for science around 1958, the true work of modern exploration developed throughout the 1950s and beyond, led by the US speleologist Russell Gurnee and his team.
Gurnee and the speleologists who accompanied him ventured into the galleries and passages of the system, mapping, measuring and documenting an underground world of colossal dimensions. It was arduous and risky work, which revealed the magnitude of the cave network carved by the river. The fruit of that exploration was captured in a book published in 1973 by Russell and Jeanne Gurnee, dedicated to the Camuy River and its caves, which made this system known to the world.
The research confirmed that it was one of the largest cave and cavern systems in the world and the most extensive in the Caribbean, with more than 200 known caves and galleries that extend for many kilometers underground, traversed by the Camuy River, one of the largest underground rivers on the planet.
The heart of the whole system is the Camuy River, which gives its name to the caves and the municipality. It rises in the heights of the island's center, in the Cerro Las Palmas area, in the municipality of Lares, and descends toward the north as a surface river until it reaches the karst's limestone strip. There the phenomenon that makes it unique occurs: the river plunges underground.
Once underground, the Camuy runs hidden for kilometers, traveling the galleries it carved itself, before reappearing on the surface farther on. The sources describe it as one of the largest underground rivers in the world, which gives an idea of the force that over millions of years bored through the rock to create this colossal cavern system.
That active-river character is at once the cause of the wonder and a risk factor: during intense rains, the river's flow increases and can flood parts of the system, forcing the park to close for safety. The river that created the caves thus continues to set the rhythm of the visits and to remind us that this is a living, dynamic ecosystem.
After decades of exploration and of becoming aware of the extraordinary value of the system, the government of Puerto Rico decided to turn part of these caves into a park accessible to the public. In 1986 the Río Camuy Cave Park was officially inaugurated, transforming this underground world into an ecotourism attraction with guided tours, trails and walkways set up for visitors of all ages.
The park opened to the public only a part of the enormous system — traditionally centered on the spectacular Cueva Clara and on lookouts like the Tres Pueblos Sinkhole one — enough for visitors to marvel at the gigantic chambers, the millennia-old formations and the underground river, while most of the network remains reserved for specialized speleology and conservation.
Since its opening, the Río Camuy Cave Park became one of the most famous and visited natural attractions in Puerto Rico, a symbol of the island's natural heritage and of the value of the karst. Each year it welcomed crowds who came to see this underground treasure, consolidating it as one of the great tourist wonders of the Caribbean.
In recent decades, the Río Camuy Cave Park has faced major challenges. The hurricanes that have battered Puerto Rico — especially the most severe events of recent years — caused damage to the park's infrastructure, access points and facilities, and forced prolonged closures. Added to that were the need for maintenance and safety work, given the complexity of operating a park within an active cave system.
As a result, the park's operating status has been variable: it has been closed for long periods and has had partial reopenings. That's why today it's essential that anyone interested in visiting check in advance whether the park is open, the hours and the available tours, rather than taking it for granted.
Beyond its tourist value, the Río Camuy Caves play a key ecological role: they're habitat for bats and other species, and the karst system is vital for the aquifers that supply water to the north of the island. Its conservation is, therefore, an environmental priority. Closed or open, the caves remain one of the great natural wonders of Puerto Rico, testimony to the slow and powerful work of water and time on the karst rock.