The Camui River Cave Park is a system of ancient caves that are located in the southwestern area of Puerto Rico. A tropical underground river flows through the caves, the third largest submarine river in the world, which took 45 million years to carve its own unusual labyrinths in the solid stratum of cave rocks. A small but extremely interesting part of the underground territory is open for tourists to visit the cave system - three crater drainage wells and two caves. Currently, out of 800 halls, only about 220 have been examined. Visitors move on a special tram. Begin the inspection from the huge Cueva Clara cave, moving along the suspension bridge to the karst well Tres Pueblos Sinkhole, from where you can see the rugged underground river Rio Camuy. The next 100-year history of the Spiral Sinkhole drainage karst well is 250 steps down. This is a spiral well that was once a huge cave. In the second Cueva Catedral Cave, petroglyphs of the Taino Native Indians engraved on the walls, who believed that the moon and the sun had once come out of the caves. The Kamui River Cave Park is famous for its many fantastic caves, making it one of the best places in the world for speleology. When visiting this wonderful park, there is a noticeable contrast when after the hot sun in the tropics you go down to the cave of the cave kingdom, where you can see stalactites and stalagmites of bizarre shapes. You can try water from a pure local spring of "Source of Youth".