This 2295Ha national park is unique in that was created to protect an area of great geological and speleological interest rather than to conserve a particular habitat. (Speleology is the study and exploration of caves). The park lies roughly mid-way between Nicoya and the mouth of the Tempisque River in a highly terrain punctuated by limestone peaks that have been uplifted into coastal hills over 500 meters. This area emerged from the sea about 60 million years ago, and since then millennia of rain have eroded the calcareous rock and filtered below to create underground waterways, chambers and vaulted ceilings. The series of approximately 42 deep caves, some in excess of 200 meters.

The caves come complete with stalagmites, stalactites and host of beautiful and lesser known formations with intriguing names such as fried eggs, organs, soda straws, popcorn, curtains, columns, pearls, flowers and shark's teeth. Spectacular stalactites and stalagmites are at their best in the caves of Terciopelo (55m deep); Trampa, which have a vertical 52m drop, and Santa Ana, the deepest with 249m. Pozo Hediondo attracts hundreds of bats and in Nicoa pre-Columbian human bones and artefacts have been discovered, although who these people were or how they got into the caves remains a mystery. Cave creatures including bats, sightless salamanders, fish in the streams running through the caves, and a variety of invertebrates live in the underground system.

Outside these caverns is a very hot, tropical dry forest, best appreciated from the lookout point above the caves. Wildlife is scarce but you may spot a racoon or coati-mundi, coyotes, a flock of orange-fronted parakeets or white-faced monkeys.

22 km east of Nicoya, Guanacaste
Opening hours: Daily, from 8:00 to 16:00