Ключевые слова: abandoned, adventure, ancient, attraction, beautiful, canyon, cave, cavern, coal, dark, deep, environment, explore, geology, green, grotto, hole, in trance, inside, lamp, landscape, light, limestone, man, mine, mineral, mountain, mysterious, nature, old, park, person, river, rock, shadow, silhouette, south, speleology, stone, sunlight, toilet, tourism, travel, tunnel, underground, vietnam, wilderness,