Camuy River Cave Park

If you take only one sightseeing trip from San Juan, this should be it. From Arecibo, on the north shore, go southwest along Route 129 to the Río Camuy Cave Park. This incredible 268-acre park is the site of the great subterranean caverns carved out by the Camuy River over one million years ago. The impeccably maintained trails gently descend 200 feet through a fern filled ravine to the yawning, cathedral-like caverns. The caves are home to a unique species of fish that is totally blind. To visit this pristine site is to be transported to another, hidden world. Rio Camuy Cave Park is the third-largest cave system in the world. Sixteen entranced have been found and 11 kilometers (7 miles) of passages explored so far. One special attraction is the Cueva Clara, which measures 695 feet (210m) in length. The park is equipped with picnic areas, walking trails, food facilities, and exhibition hall and a souvenir shop, making it the perfect place to spend a day.