Metallica are arguably the most widely known and commercially successful heavy metal band of all time, with an estimated 120 million albums sold worldwide. Formed in Los Angeles, in 1981, before relocating to San Francisco two years later, Metallica helped both spearhead and define the thrash metal genre with a quartet of classic ‘80s albums. In the ‘90s, vocalist/guitarist James Hetfield, drummer Lars Ulrich, lead guitarist Kirk Hammett and bassist Jason Newsted (who replaced the deceased Cliff Burton, in 1986), embraced more accessible sounds and new compositional styles, to the chagrin of some diehard fans. But the band’s remarkable career momentum did not suffer until the early ‘00s, when an ill-advised skirmish with the file sharing network Napster combined with the poorly received ‘St. Anger’ album and assorted personal demons (all of them painfully documented by the infamous feature-length documentary, ‘Some Kind of Mon-ster’) to threaten the band’s future. Metallica duly recovered, however, with the help of new bassist Robert Trujillo, a back to basics LP (2008’s ‘Death Magnetic’) and a never flagging stadium-packing capacity across the globe.