An underground Christmas celebration sure sounds edgy and cool, but little could prepare visitors for this literally underground venue. Natural Bridge Caverns, just on the edge of San Antonio, is hosting its 10th Christmas at the Caverns "season of celebration," but this one adds even more shimmer to these dark depths.

The classic traditions are returning, starting on December 2: an above-ground trail of lights that stretches a third of a mile (with some new additions), a 30-foot Christmas tree, a visit from "Spelunker Claus" and Mrs. Claus. More unusual, the 5,000-square-foot "Reindeer Roundup Maze" gives kids a festive mission, and "Caroling in the Caverns" brings more professional singing groups back for resonant performances in the stunning underground space.

Now the festivities are extended five days, through December 30, and a concert series is added to the holiday lineup. Like the caroling, it also takes place inside the caverns — this time in a newly developed space dubbed by a release "the deepest underground event venue in Texas."

The concert series already exists, but Christmas brings a new set of visitors who may not have experienced the musical spectacle. Photos highlight the unique offering, highlighting performers bathed in light from nowhere amid the quasi-cathedral natural environment. Considering the acoustics, it's almost weird that we don't have more concerts in caves.

"Our 'Live Underground' concerts have been so popular, when we were looking for a way to celebrate our 10th anniversary, it seemed like the perfect way to extend the festivities," said President of Natural Bridge Caverns Brad Wuest in the release.

So far there are three artists scheduled to play during the holiday series:

• Zack Walther Band on December 21
• Scotty Alexander on December 26
• Matt Castillo on December 28
• Payton Howie on December 29
• Clay Hollis on December 30

It's not all just entertainment; in the spirit of the holidays and Christmas at the Caverns tradition, the venue will be collecting food and financial donations for the New Braunfels and San Antonio Food Bank. It will also donate a portion of ticket sales, adding to its previous cumulative donation of $125,000 and 1.25 million pounds of food.

While visitors are there, they might as well take some of the year-round tours that will still be running throughout the holiday festivities. A concert ticket also gets guests into all of the other holiday events, and there are multiple other ways to organize a visit. Tickets for Underground Live Concerts are available at naturalbridgecaverns.com.