Metallica formed in Los Angeles on October 28, 1981, when drummer Lars Ulrich and vocalist/guitarist James Hetfield responded to Ulrich's newspaper ad. They recruited bassist Ron McGovney and lead guitarist Dave Mustaine, later relocating to the San Francisco Bay Area after replacing McGovney with Cliff Burton in 1983 and Mustaine with Kirk Hammett. The band's style features fast tempos, aggressive riffs, and complex instrumentation, establishing them as a founding member of the 'Big Four' of thrash metal alongside Megadeth, Anthrax, and Slayer. Their debut album, Kill 'Em All, released in 1983 via Megaforce Records, was followed by Ride the Lightning (1984) and Master of Puppets (1986). The self-titled Metallica (1991), known as the Black Album, sold over 16 million copies worldwide and earned Grammy and other awards. Lineup changes included Burton's death in 1986, Jason Newsted's addition in 1986, his departure in 2001, and Robert Trujillo joining in 2003. Metallica maintains an active touring schedule, known for extended live performances featuring their catalog of songs.