The Venado Caverns (also know as the Spanish Caverns) were formed during the Miocene Period, between 15 and 20 million years ago. As a result of tectonic plate movement, the once water-covered caverns are now part of the earth’s surface. They contain a variety of interesting formations including limestone, stalactites, stalagmites and coral.
The bus to the Venado Caverns is the same bus that travels to La Fortuna and the Arenal volcano. A tour in the caverns will cost about US $60, which includes boots, a helmet, a flashlight, a guide and transportation.