Barra Honda is unique among the National Parks of Costa Rica: its main attraction
is an intricately large system of limestone caverns which house a multitude of capricious
forms and figures. 

Barra Honda is a 450 m high, nearly flat mesa looming 300 m above the Tempisque
valley. It mainly consists of coral reef aging over 60 million years. Tectonic faulting has
 uplifted the area from the seabed 70 million years ago and rains created underground
waterways. The constant dropping of rainwater on calcium carbonate has then created
these underground art galleries - fancies of nature grown over millenniums of years.