Ключевые слова: ancient, carlsbad, cave, cavern, caverns, caving, dark, darkness, den, erosion, formation, formations, geological, geology, grot, grotto, highlighted, hollow, inside, light, limestone, mineral, natural, nature, rock, stalactite, stalactites, stalagmite, stalagmites, stone, subterranean, tourism, underground, view, water, water drips,