Ключевые слова: ancient, arch, attraction, catacombs, cave, cavern, caving, corridor, dark, deep, digging, earth, empty, entrance, excursion, gallery, geology, grotto, history, hole, holiday, inside, interior, level, light, limestone, mine, mineral, mountain, mystery, passage, perspective, place, quarry, rock, sandstone, speleology, stone, structure, tourism, tunnel, underground, underpass, wall, wet,