hi there, Arecibo Puerto Rico is home to a large acre park called Rio Camuy, which features miles of underground caverns carved by the Camuy River, the third largest cave system in the entire world. The Arecibo park is also a great place to observe a variety of amazing wildlife, including a species of fish that is completely unique to the area. Arecibo Puerto Rico is also well known for its observatory, the Arecibo Observatory, which is home to the largest single-unit radio telescope in the world. Hope this helps Vacationbuddy