Metallica is an American heavy metal band based in San Rafael, California. The band was formed in 1981 in Los Angeles when vocalist/guitarist James Hetfield responded to an advertisement posted by drummer Lars Ulrich in a local newspaper. Metallica's current line-up comprises founding members Hetfield and Ulrich, longtime lead guitarist Kirk Hammett and bassist Robert Trujillo. Guitarist Dave Mustaine and bassists Ron McGovney, Cliff Burton and Jason Newsted are former members of the band. The band's fast tempos, instrumentals, and aggressive musicianship placed them as one of the founding "big four" bands of thrash metal, alongside Anthrax, Megadeth, and Slayer. Metallica earned a growing fan base in the underground music community and won critical acclaim with its first four albums; their third album Master of Puppets (1986) was described as one of the most influential and heaviest of thrash metal albums. The band expanded its musical direction and achieved substantial commercial success with its eponymous fifth album Metallica (1991), which resulted in an album that appealed to a more mainstream audience. The album was also their first to debut at number one on the Billboard 200, a success that they also achieved on their following five studio albums