Earth has benefited from all of these.

地球拥有一切条件

An environment that remains relatively stable

一个相对稳定的环境

for complex life to survive.But there's a curioustwist.

是复杂生命存活的关键 但是还有一个特别的曲折

Too much stability and evolution can get stuck in a bit of a rut.

太多的稳定和进化会造成重蹈覆辙

Every now and then life needs a catastrophe to shake things up.

时不时地生命需要灾难来改变现在

In the jungles of Mexico lies the evidence of one such catastrophe,

在墨西哥的一个丛林里 就有证据证明这样灾难的存在

one that turned out to be very important for us humans.

这次灾难对于人类来说非常重要

You know, everywhere you go around here, you find these holes.

不管你走到哪里都能发现这样的坑

They're called cenotes.

他们被称作沼穴

There's thousands of them and most of them haven't even been explored.

有好几千个 大部分都还没有被探索

But these are the right people to be with because these guys are cave explorers

这些人正是我们需要的 因为他们就是沼穴探索者

and they're going to show me a new world.one beneath our feet.

它们要为我们打开一个新的世界 就在我们脚下

Team leader Bernadette is the first to descend.

小组领队伯纳德特第一个下去