It was a rather inauspicious beginning, this Feb. 10, 1970, concert at a Knights of Columbus Hall outside of Houston.

Billy Gibbons had just added the final pieces – Dusty Hill and Frank Beard – to what would become ZZ Top's long-running current lineup when Al Caldwell, a radio personality at KLVI in Beaumont, booked their first gig together. "There was one person in the audience," Billy Gibbons has joked, "so we bought him a Coke and finished the rest of the show."

A series of similarly forgettable shows followed while ZZ Top, started by Gibbons in late 1969, coalesced around Beard and Hill. They were a long way from fuzzy-guitar-spinning stardom, as illustrated by a period photo (see above) taken during a May 1970 appearance at the Little Cypress-Mauriceville High School prom. The group is identified as "Zee Zee Top," something Gibbons chalked up to a "yearbook club error" after it made the rounds on the internet a couple of years ago. "There’s not a day that goes by where somebody doesn’t say, ‘Hey, I saw this funny picture of you guys. When was that?" Gibbons told Texas Monthly.

Back in 1970, the only one sporting a beard was Hill, and it was a fraction of the iconic modern-day length he now sports, alongside Gibbons. As their facial hair grew, so did ZZ Top's legend. But it took a while. ZZ Top's First Album followed in 1971, and sank like a rock, and 1972's Rio Grande Mud didn't fare much better. It was 1973 before Tres Hombres finally hurtled ZZ Top into the U.S. Top 10.

And it all started at a tucked-away spot, in front of a largely empty room on old U.S. 90 in Beaumont, Texas. "I had to borrow a bass for that gig. I didn't actually own one," Hill told the Houston Chronicle. "It was the Knights of Columbus Hall and though I didn't meet any knights or royalty, there were a lot of cool people who came out to hear us play. And so it began."