Ключевые слова: adventure, below, calcite, cave, cavern, caverns, danger, dangerous, dark, dirty, earth, exploration, formation, geology, grotto, hiking, landscape, large, mountains, national, nature, outdoor, outdoors, park, risk, risky, rock, scenery, speleology, stalactite, stalactites, stalagmite, stalagmites, stone, trail, travel, tunnel, underground,