The ancient Venado Caves are a geological marvel, shaped by tectonic shifting and an underground river.

The Venado Caverns, a 2,700 meter stretch of limestone caves replete with stalactite and stalagmite formations, are ideal for a day-trip from nearby Arenal. The caverns, believed to be between 15 and 20 million years old, were formed by underground streams which still run through the caves.

During the guided tour of the caverns, you may see bats, monochrome frogs, fish and marine fossils, many of which are endemic to the area.