Hidden Caves

[pdxfj]

I came across this the other day.  Needless to say it's an amazing find to the geological world.  A hidden cave that was only discovered a year ago that you can fit a sky scraper into.

Hard to wrap your mind around it.

http://ngm.nationalgeographic.com/2011/01/largest-cave/jenkins-text

[CMD]

Now they are amazing photo's 
Amazing isn't it that Man can explore space when he knows so little about his own planet