Luray Caverns is the largest cave system in the Eastern United States, and listed as a National Natural Landmark.
Portions of the cave system are lighted and open to the public, for a fee of course.
The trip is certainly worth the fee though, with an organ that taps out notes on different sized rock formations like a pipe organ, underground mirror pools, and a wishing well that is supposedly filled with coins three feet deep.
Peaks and Valleys
These stalactites look like an upside-down Himalayan mountain range.
Predator
Stalactites and their combined reflection look like the teeth of the alien in the movie Predator.
Down and Down
The stairs winding down through Luray Caverns wind you through massive formations.
Wide Open Spaces
You can get a feel for the size of this cavern with the people in the shot for a reference point.
Future Funds
A pool inside the caverns filled with coins and dollars that people have pitched in. The money is periodically collected and donated to a charity.

