Slovakia: Domica Cave (Slovak Karst NP)
Domina Cave is the largest and most spectacular cave in the Slovak Karst National Park – massive cathedral like rooms with stalactites and stalagmites and columns and flowstone everywhere – all the classic cave formations are here hued in red and orange and black (the latter is manganese). It’s the most popular cave in Slovakia and crowds gather to get in. About 2km of underground passages are available for exploration. This cave is also on the UNESCO World Heritage List.