The Rio Camuy Cave Park features a huge cave system covering 268 acres and is thought to be the third largest cave system in the world. A trolley bus transports visitors to a 200-foot deep cave, or sinkhole, which is now a preserved area known as Cueva Clara Empalme. The caves feature various rooms, in some cases with extremely high ceilings, stalagmites, and stalactites, and rivers rushing along the base. A guided tour leads visitors through the Cueva Clara Empalme. In addition to the natural wonders the cave system presents, it's also interesting to note that the caves were used by the indigenous population long ago.