These images of Vietnam caves from National Geographic's January 2011 issue are incredible! The largest cave discovered, Hang Son Doong, is large enough to accommodate a block of New York skyscrapers! It's amazing to think of exploring these caves and seeing this whole other world.
One of my favorite field trips was when my high school biology class went spelunking in Illinois caverns. It was a small cave, and there were a few tight squeezes, but overall I really wasn't scared (unusual for me). I loved seeing the stalactites and stalagmites and wading through the underground streams. I remember one area where the water was rushing and we slid down the rocks like a water slide! It was a fun little adventure.
Now I'll just have to explore through pictures.....
Photography by Carsten Peter
More cave photos here