洞穴探险

We found some really interesting caves, but we didn't have the gear to go spelunking.

我们发现一些相当有趣的洞穴，但我们没有装备去进行洞穴险。

It may also be referred to as "draining" (when exploring drains) "urban spelunking", "urban caving", or "building hacking".

它同称为“下水道”，“城市洞穴险”，“险”等等。