Ключевые слова: cave, cavern, caving, dark, deep, discovery, dripstone, dropstone, europe, formation, gallery, geologist, geology, hall, heritage, illumination, inside, karst, landmark, landscape, limestone, mineral, minerals, natural, nature, postojna, rock, slovenia, stalactite, stalactites, stalagmite, stalagmites, stone, tour, travel, underground,