Metallica didn’t just help invent heavy metal, they evolved with it. Formed in 1981 when a “dorky, disenfranchised” teenager in Orange County, California—Lars Ulrich, his words—placed a classified ad name-checking Iron Maiden and Diamond Head, the band debuted in 1983 with Kill ’Em All and pioneered the blinding synthesis of punk and British metal we now call thrash. Having moved to the Bay Area in the early ’80s to court bassist Cliff Burton, the band—Ulrich, guitarist Kirk Hammett, guitarist-vocalist James Hetfield, and Burton—went on to fashion metal into a kind of art form, eschewing the glammy appeal of hair metal for ultra-serious, progressively complex song-suites that explored subjects like suicide, political corruption, and the psychological horror of war. (Burton was killed in a bus accident in late 1986 and replaced by Jason Newsted; the band regrouped for 1988’s epochal … And Justice for All.) Even as they became a global phenomenon in the wake of 1991’s record-breaking self-titled album, Metallica remained defiantly on their own path, dabbling in Southern rock (1996’s Load), high-concept dirges (2011’s divisive Lou Reed collaboration Lulu), stripped-down hardcore (2003’s St. Anger), and orchestral live albums (1999’s S&M). Their story is, in essence, the story of metal itself: a push-pull of simplicity and complexity that continually challenges our understanding of fast and loud.