Salt water, unlike fresh water, does not erode limestone, 咸水与淡水不同 不会溶解石灰岩

210. The Maya understood the importance of the cenotes,
     玛雅人知道沼穴的重要性
211. but they could never have known that these flooded passageways were actually the beginning of subterranean rivers,
     但他们从不知道这些水下通道 其实是地下河的入口
212. all of which eventually flow out to the sea.
     它们最终都流向大海
213. Salt water, unlike fresh water, does not erode limestone,
     咸水与淡水不同 不会溶解石灰岩
214. so most sea caves are created by the mechanical pounding of the waves.
     所以大部分海洋洞窟 是在海浪的机械冲击下形成的
215. The rocky outcrops of New Zealand's Poor Knight Islands are riddled with sea caves
     新西兰坡·骑士岛的 岩礁下布满了海蚀洞
216. and just like those in Borneo
     与婆罗洲的洞窟一样

来自《行星地球 第一季 第四集 Planet Earth S01E04 洞穴》第 213 行