Ключевые слова: abstract, ancient, asia, beautiful, cave, cavern, chuko, dark, darkness, exotic, exploration, explore, gangala, geological, geology, gyokusendo, hall, japan, journey, landscape, light, limestone, natural, nature, okinawa, rock, scenic, speleology, staircase, stairs, stalactite, stalagmite, stone, tourism, travel, tunnel, wall,