Volunteers at Cherokee Caverns near Oak Ridge have spent the last month hanging more than 20,000 Christmas lights and decorations inside the cave.
Families can walk the mile loop inside the cave which stays a balmy 58 degrees year round.
Also, families can take a picture with Santa and, of course, learn about mother nature.
The Director of Cherokee Caverns, Jim Whidby, says, "They can enjoy a wide variety of cave formation, stalagmites, stalactites, androdites. I encourage folks to come out and enjoy the beauty of the cave. It is the most historical cave in Knox County.The only one of 171 caves that was open to the public."
"Christmas in the Cave" runs Friday and Saturday night from 5:30 p.m. to 8:30 p.m. and next Thursday through Sunday. Tickets are $8.