Photo by Tom Schulte
There are many caves along the Blue Ridge Mountains and Shenandoah Valley, but only this one has a "Great Stalacpipe Organ" in the cave that can be played for you by means of mallets against the stalactites. Luray also has wonderful cave formations for enthusiasts and spelunkers.
If you go:
Fee charged, but it is one of the best values in the area. You can exit and enter the Skyline Drive to visit the cave.
Links:

100 Cave Hill Road
Luray, Virginia 22835 USA
Mailing address:
Luray Caverns
970 US Hwy 211W
Luray, VA 22835 USA
Phone Numbers:
Luray Caverns
+1 (540) 743-6551
+1 (540) 743-6551