the water takes on a new, more erosive power. 水便有了一股新的、更强的侵蚀力
Today caves remain the least explored places on Earth. 今天 洞穴仍是地球上 人类最少涉足的地方
Here, live some of the strangest and least-known animals on the planet. 这里住着一些地球上最奇异 和最鲜为人知的动物
Yet these depths were first explored only two years before man landed on the moon. 然而人类直到登月前两年 才第一次进入这个深渊
and form one of the most productive habitats on the planet. 成为地球上一处 最肥沃的野生动物栖息地
to rest and refuel on their long migratory journeys. 并在此休整 准备继续长途迁徙
Iguassu Falls on the border of Brazil and Argentina 位于巴西和阿根廷边境的伊瓜苏瀑布
In these murky waters they rely on sonar to navigate and hunt. 它们利用回声定位 在昏暗的水中探路和捕食
On its way the system drains a third of South America. 全部流域面积达到南美洲的1/3
80 percent of its species are found nowhere else on Earth, 湖里80%的物种 在地球上其它地方都不存在