Costa Rica, is a young region from the geologic point of view. In fact, until few millions of years ago, there was anything but water between North America and SouthAmerica. 

 

The apparition of submarine volcanos and the contact between the tectonic plates, work together and they form Central America, from which Costa Rica is part. 

 

The contact between " Cocos " and " Caribe " plaques caused that regions that were under the sea, elevate over their original level, transforming what in that time were underground rivers in majestic caverns, whose stalactites and stalagmites formations (formed through thousands of years) are a real masterpiece of nature.