Slovakia: Gombasek Cave (Slovak Karst NP)
Slovak Karst National Park cover a varied limestone terrain housing hundreds of kilometers of caves. Several most spectacular caves are listed as UNESCO Heritage Sites, Gombasek is one of them. It’s not a massive cave and only about 1km of narrow passages are walkable for tourists. But it’s extremely colorful, mostly orange and red due to iron oxide presence. The cave also is famous for the very fragile soda straw formations, some almost 3m/10ft long.