Metallica is an American heavy metal band formed in Los Angeles in 1981 by vocalist/guitarist James Hetfield and drummer Lars Ulrich. They are considered one of the founding "big four" bands of thrash metal, alongside Megadeth, Anthrax, and Slayer. The band is known for fast tempos, instrumentals, and aggressive musicianship. Metallica has had several members over the years, with the current lineup including Hetfield, Ulrich, lead guitarist Kirk Hammett, and bassist Robert Trujillo. They achieved major commercial success with albums like "Master of Puppets," "...And Justice for All," and their self-titled album "Metallica" (also known as The Black Album). Metallica is one of the biggest-selling music acts in history and is highly influential in the heavy metal genre.