The area of the Tempisque Basin where the Nicoya Peninsula joins the mainland has a foundation of relatively soft limestone. Water has cut extensive caves through Cerro Barra Honda and the other small mountains creating the best know feature of this National Park. However, the park also has well maintained hiking trails. The protected tropical dry forest (though mostly secondary) within its borders is some of the last in the world, and very different from the rain and cloud forests that attract many ecological tourists to Costa Rica.

Exploration of the Caverns at Barra Honda require specialized spelunking equipment and an authorized guide. (USFW)

The Caverns
The soda straws, pearls, roses, needles, cave grapes, curtains, terraces, stalactites, stalagmites and other calcareous formations of the more than 40 limestone caverns are the main attraction at Barra Honda National Park. The caves are all in relatively good condition because their vertical entrances are difficult to negotiate. This is also why you need climbing gear, a guide, and permission from the Parks service in advance to enter them.

The caves range from a few feet to over 780 feet (240 meters) deep. Pozo Hediondo (Fetid Pit) Cave was named for the aroma of the guano deposited by thousands of resident bats. Until the caverns were discovered and explored in the late sixties, many belived that Cerro Barra Honda was a volcano because of the roaring sounds made by the bats as they departed the caverns en masse, and the fumes from the caves they occupied.