Ключевые слова: adventure, am phu, arch, asia, asian, beautiful, cave, cavern, caves, caving, ceiling, da nang, dark, deep, destination, dong, formation, geologic, geological, geology, golden, grotto, hole, huyen khong, indochina, inside, interior, landmark, landscape, light, limestone, marble, marble mountain, marble mountains, mineral, mountain, mountains, natural, nature, old, rock, scenic, speleology, stone, travel, tunnel, underground, vietnam, vietnamese, wall,