On a page commemorating Frank Zappa’s induction, the Hall of Fame shares that Zappa “used his prodigious musical talent to challenge the status quo. Frank Zappa was an outspoken critic of everything from the herd mentality of the middle class to censorship of rock and roll. In his career, he worked with every genre … and produced 60 radical, groundbreaking and irreverent albums” (via Rock and Roll Hall of Fame). In 1986, he won a Grammy Award for his “Jazz From Hell” album and received a Grammy Award for Lifetime Achievement in 1997.

The eccentric artist died on December 4, 1993, after a two-year battle with prostate cancer. “Composer Frank Zappa left for his final tour just before 6 p.m. Saturday,” his family announced in a statement at the time (via Los Angeles Times). He was buried in an unmarked grave, near musician Roy Orbison, who was also laid to rest at an unidentified site in Westwood Village Memorial Park in Los Angeles. It’s unclear why Zappa’s grave was unmarked, but speculation has it that either his family worried about vandals or that the musician didn’t want any identifying tombstones or special remembrances (via the BBC).