The words “stoner epic” don’t even come close to describing the extreme riff-hypnosis that Jerusalem visited upon the red-eyed legions of heshers, grass pirates, and acid casualties who genuflected at the altar of the legendary San Jose power-trio known as Sleep.

In 1989, while the extreme metal underground was bingeing on the high-speed savagery of death metal and grindcore, ex-Napalm Death vocalist Lee Dorrian and Carcass roadie Mark “Griff” Griffiths were getting ripped on British cider, brown weed, and the down-tuned Sabbathian histrionics of Trouble, St. Vitus, and Witchfinder General.

In the Norwegian summer of 1993, the second wave of black metal was still in its ultra-violent infancy, and only a handful of bands were actively exploring the parameters of what was then an obscure and distinctly Scandinavian art form.

1999 was a transitional year for both underground music and America’s most iconic freestanding structures.

Hearken back to when you first slapped on Calculating Infinity. Recall how completely overwhelmed you were by the Dillinger Escape Plan’s virtuosity, originality, technicality and songs seemingly designed to induce vertigo.

Liverpudlian grind titans Carcass may not have invented grindcore with 1991’s Necroticism – Descanting the Insalubrious, but they certainly opened it up to a magnitude of previously unfathomed possibilities.

Death metal was still in its infancy when Left Hand Path came roaring out of Stockholm like Satan’s official theme music—a deafening cavalcade of impossibly thick guitars, guttural vocal incantations, and gore-drenched lyrics that struck a considerable contrast—well, the guitars, anyway—to the burgeoning Floridian death-swarm (Obituary, Death, Morbid Angel) of the day.

1987 was a big year for coke-metal and bad hair: Def Leppard’s Hysteria, Mötley Crüe’s Girls, Girls, Girls, Whitesnake’s Whitesnake, and Guns n’ Roses’ Appetite For Destruction were all bum-rushing the charts like a pack of wild junkies tearing through Steven Tyler’s medicine cabinet at 4AM—which most of them were, anyway.

Northern England, 1990. Amid the cacophony of blast beats echoing from the speed obsessed world of UK death metal and grindcore, five lads from the grim North were feverishly gathering songs and ideas for the follow up to their doom laden debut album Lost Paradise.

When I was sixteen years old, I listened to four records obsessively: Metallica’s …And Justice For All …, Kyuss’ Blues For the Red Sun, the first Danzig album, and Life Of Agony’s River Runs Red—the last of which I thought was my own private musical discovery (like every other jackass with cable, I saw the video for “Through And Through” on Headbanger’s Ball).