Four amateur explorers, members of the Kentucky-based nonprofit Cave Research Foundation, discovered a giant, crystal-filled cave in California's Sequoia National Park. This cavern is being hailed as a major find that will help expand knowledge of geologic hisotry and the formation of caves throughout the West.  For more information on this discovery, read here.

Personally, I have always found caverns to be amazing places to visit and I even took a 'Walk on the Wild Side' tour of Cave of the Winds in Colorado about 12 years ago when my husband and I were on our honeymoon. It was a tour off the beaten path. We were advised to wear old clothes (which we actually threw away when we were done). It was really neat, though a bit tight in places and a couple of places I didn't venture into. At any rate, if you have never gone on a tour of an underground cavern, I highly recommend it! There are so many amazing things to see in these underground worlds! Go here for the USGS site on caves and loads of information! Go here to locate caverns near you.