Something really, really cool lurks about an hour and half southeast of Nashville. Well, 83 miles southeast and then another 333 feet down at the foot of Monteagle Mountain. That's where Bluegrass Underground takes place, in the Volcano Room of the Cumberland Caverns.
Some of the best bluegrass, gospel, jazz, country, Americana, roots and rock bands take the "stage" inside and perform to adoring, if not adventurous crowds. From Vince Gill and Chris Stapleton to Old Crow Medicine Show and Jason Isbell, some of the best singers and songwriters of the day all graced the limestone platform.
To make it to the Volcano Room, you need a 15-minute walk inside the cave's entrance. Eventually, you'll happen upon a giant crystal chandelier and lighting trusses cling to the ceiling like stalactites. Except instead of forming naturally millions of years ago, these fixtures came a few years back to add a little ambiance. As if you need more ambiance than a massive cave.
If the whole thing sounds a little like something out of Batman, it kind of is. Well, in the sense that there are actually bats liable to watch the show right alongside the 600 or so fans.
Cumberland Caverns, of course, didn't always host musicians. Aaron Higgenbotham discovered the cave in 1810 and since then it served various purposes. But 1956 saw the cave first open to the public as an attraction. As it turns out, Cumberland Caverns is the second largest cave structure in Tennessee. In fact, it's the second largest east of the Mississippi River, stretching on for 32 miles.
But in 2008, Nashville businessman Todd Mayo took an hourlong tour with his family over Memorial Day weekend. When Mayo came to the Volcano Room, he immediately saw potential.
"It's just like you're on another planet," Mayo tells NPR. "And I said to the girl, just like that, without even thinking, 'Do y'all ever have live music down here?' And she said, 'No, but that'd be a pretty good idea.'"
Mayo returned to Nashville and approached the famed WSM about partnering up to broadcast performances and interviews from the caverns on the radio. But first, they needed to see if music even sounded good in the room. Or if it sounded, you know, like a cave.
Mayo brought in Grammy-winning sound engineer Phil Harris and bluegrass artist Chris Volpe to test out the acoustics. The results were surprising.
"The natural acoustics in the Volcano Room rival the finest studios in Nashville," Harris tells Blue Ridge Outdoors. "Taken with the cave's natural features and 350 million years of evolution, there isn't another performance space like it anywhere on the planet."
Any number of factors contributes to the incredible sound. For one, there aren't any parallel or even surfaces, which usually create unwanted reverberations from the sound waves. Additionally, the humidity and general softness of the limestone all contribute to a sonically warm, controlled environment.
"Sonically" is the operative word in "sonically warm." Because the actual temperature of the Volcano Room sits rights around 57 degrees, pretty much year-round. Even in the dead of summer, fans bring blankets to wrap up in for the intimate performances.
So after Mayo knew he had a great room and willing partners in WSM and Cumberland Caverns, everybody was on board. "It was a marketer's dream," Caverns manager Teddy Jones told USA Today. "We're now the opening act for the Grand Ole Opry, for goodness sake. People come here from all over the country for the show, and it's a great tie-in for us."
After several successful radio shows, Mayo almost immediately expanded to television. He and producer partner Todd Jarrell took the concept to PBS in 2010, where the show gained traction. They began filming the "seasons" of concerts to air all across the country.
Mayo envisions Bluegrass Underground taking on a role similar to the famed Austin City Limits show. However, due to the nature of the venue, they film a bit differently. All of the performances for any given season take place over a few days in the Spring. They edit them up and air them in September.
And in fact, season seven filming approaches. They'll film all 12 acts March 24-26. Acts include Marty Stuart, Conor Oberst, The Mavericks and Blues Traveler. The show claims 12 MidSouth Emmy Awards.
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But don't get too excited. Tickets for the tapings sell out almost instantly. And yet, due to the success of the show, you've got another shot.
In 2015, the Bluegrass Underground and Cumberland Caverns opened up the venue to more than just tapings. And to more than just roots music. Dubbed "Live From The Underground," the concert series take place 25-35 times per year. Events currently on the schedule range from Pam Tillis to Billy Bob Thornton to Grammy-nominated up-and-coming rock trio Highly Suspect. Other artists who have played include Marty Stuart and his Fabulous Superlatives, Widespread Panic, the Chris Robinson Brotherhood, Drew Holcomb and the Neighbors and the McCrary Sisters.
Check out the expanding list of events and be sure to get tickets early. Even though they don't go quite as quickly as tapings, many shows sell out months in advance.