Ключевые слова: abstract, amazing, ancient, asia, asian, background, beautiful, bo trach, cave, cavern, color, formation, geological, geology, grotto, heritage, impression, impressive, indoor, inside, ke bang, kebang, limestone, national, natural, nature, phong nha, phongnha, quang binh, quangbinh, shape, speleology, stalactite, stalagmite, stone, thien son, tourism, tourist, travel, viet nam, vietnam, water, wonderful, world,