LIVERPOOL, England (AP) – The stuffy cave-like club where the Beatles staged some of their earliest performances celebrated its 50th birthday Tuesday.

The Cavern Club a former fruit warehouse cellar and air raid shelter opened as a jazz venue in 1957 with the Merseysippi Jazz Band, but it was the advent of rock `n’ roll that popularized the club where music producer Brian Epstein eventually discovered the Fab Four.

John Lennon’s sister, Julia Baird, works at the club and says those early performances were important for her brother.

“John felt he was the raw-edged rocker he wanted to be on this stage before being polished up,” Baird told The Associated Press. “He regretted the way they were later smartened up, pulled into suits and ripped out of their leathers.”

The Beatles first played a lunchtime session in 1961, but Lennon and Paul McCartney both appeared at the club with the Quarrymen Skiffle Group years before. Ringo Starr is also thought to have made his debut at the club with the Eddie Clayton Skiffle group another band playing the improvised form of jazz popularized in Britain in the 1950s while George Harrison appeared at the group’s 1961 debut.

After struggling to survive, the club was demolished in 1973 but was rebuilt on half of its original structure in 1984. Bands from Argentina to Russia played in a 13-hour session to honor its anniversary on Tuesday.

The Cavern now also has venues in Australia, Argentina and Japan.

On the Net: Cavern Club: http://www.cavern-liverpool.co.uk