picturesque karst features illuminated in the cave, postojna grotte

ancient archeology arid cango cave cavern cliff damp dark discovery east espeloelogo europe feature geologist geology historical history jama karoo karst klein landmark landscape limestone little minerals monument nature oudtshoorn postojna postojnska river rock slovenia slovenija south speleological speleology stalactite stalactites stalagmite stalagmites stone system travel underground underworld water wet