Punk may have disrupted the mid-’70s arena-rock landscape with its safety-pinned insolence and roughed-up riffs, but for a certain subset of disgruntled kids, it didn’t go far enough. Enter hardcore, the more ruthless and reckless offspring genre that severed punk from its roots in garage rock and glam and put the emphasis on pure velocity and anti-pop aggression. Its origins can be traced to Southern California circa 1978, when Black Flag started pushing punk to noisier and more nihilistic extremes; over in D.C., Bad Brains and Minor Threat unlocked hardcore’s political potential by infusing their warp-speed salvos with self-empowering messaging. By the mid-‘80s, hardcore had spawned a national network of scenes united in their rejection of commercial-rock conformity and Reagan-era conservatism. But for a genre that thrives on burn-it-down anarchism and 90-second blitzes, hardcore has proven surprisingly durable, spawning a DIY ecosystem of independent record labels and venues that persists to this day, and its spirit of raging discontent lives on through 21st-century torchbearers like Turnstile.