Río Camuy Cave Park
Known for: a vast underground river cave system
The Río Camuy Cave Park, on Puerto Rico's northwest karst belt, protects part of one of the largest cave systems in the Western Hemisphere — carved over millennia by the Río Camuy, among the largest underground rivers in the world. The limestone here is riddled with sinkholes, passages, and cathedral-sized chambers. Guided visits typically descend into Cueva Clara, a vast cavern hung with stalactites and stalagmites, with views of sinkholes where the river disappears underground. It's a cool, damp, family-friendly outing; hours and tour availability vary, so confirm the park is open before making the drive into the interior.