As Libby Swanger raised her viola and began Jimmy Page’s solo from Led Zeppelin’s “Kashmir,” there was no way for her to anticipate the crowd reaction.

“People were like screaming for me, and as a violist, that has never happened ever," she said. "People don’t scream for us, and it was just like a shining moment that came out of last year.”

Swanger’s performance took place with the bluegrass group The Lonely Mountain String Band during An Under Cover Weekend, St. Louis’s annual tribute band festival. This weekend, the event celebrates its 10th anniversary.

Michael Tomko launched the weekend of bands playing covers of famous songs to attract St. Louis music fans to other events he was promoting. Tomko initially thought one big festival of music that everyone could identify would drive attention to the other shows he booked throughout the year. But the event was an instant hit. Its first venue, The Bluebird, made $11,000 in bar sales alone. Attendees cried during one band’s performance as 1980s icons The Cure. As soon as the final band left the stage, musicians began approaching Tomko about playing the following year.

Tribute band festival blurs the line between musicians and fans for tenth year The Lonely Mountain String Band performs Taylor Swift's "Style." Recorded by Students & Faculty at ex’Treme Institute by Nelly. Listen • 3:41

The event has changed over the years. The Bluebird changed hands and became The Firebird, which still houses the event. Tomko tacked on a third day of music to the event. Submissions grew from a handful that first year to more than 40. Hopeful acts are required to provide a number of band’s they’d like to cover and fill out a lengthy justification for why they should be chosen. In more than 132 sets, musicians have played a wide range of music, from The Beastie Boys to Neil Diamond, The Flaming Lips and Michael Jackson.

Tribute band festival blurs the line between musicians and fans for tenth year Too Deep perform The White Stripes' "The Hardest Button To Button.” Recorded by Students & Faculty at ex’Treme Institute by Nelly. Listen • 3:16

Tomko said the event’s success is the result of serious preparation. Several bands prepare sets a year in advance.

Jess Bohn, who sings in the band Ramona Deflowered, said her bass player has gushed over the event for the past four years. This year they decided to submit and were chosen to close the event Saturday.

In a voice tinged with reverence, Bohn described how her band will take the stage as her idol, Joan Jett.

“We’re doing costumes, we’re really paying a lot of attention to how we’re taking care of this music,” Bohn said. “It’s an honor to stand up there and even pretend that we’re Joan Jett for the night.”

Tribute band festival blurs the line between musicians and fans for tenth year Ramona Deflowered perform Joan Jett and The Runaways' "Cherry Bomb." Recorded by Students & Faculty at ex’Treme Institute by Nelly. Listen • 2:34

Swanger said that reverence unites both performers and audience members. Attendees come out to see people become the bands they love, the bands that made them want to be musicians.

“It’s really special to watch people do that in front of everybody else,” she said. “I think people connect with how much fun everyone’s having on stage.”