Urdazubi/Urdax

Urdazubi/Urdax is a village and municipality located in the autonomous community of Navarre, in the north of Spain.

Well known because of its caves, Urdax is an interesting place for speleology at a basic level. Urdax caves were created by the underground river Urtxuma 14,000 years ago, and nowadays only a single cave can be visited by the public. The only cave that is opened to those interested in it, is the Ikaburu cave where visitors can enjoy a guided visit through its corridors and stances. The Ikaburu cave tour includes more than seeing the wonderful stalactites and stalagmites, but also stories of witches, shepherds, monks, Spanish Civil War, or even contrabandists.

Wikipedia