Ключевые слова: attraction, beautiful, cave, cavern, caves, caving, column, dark, deep, europe, formation, geologic, geologist, geology, grotte, grotto, inside, interior, jama, karst, landmark, light, limestone, mineral, mountain, national, natural, nature, postojna, rock, slovenia, speleology, stalactite, stalactites, stalagmite, stalagmites, stone, tourism, train, travel, tunnel, underground, wall,