Birmingham, England, 1965: an industrial suburb of London. This is a city still living in the shadow of the Birmingham Blitz, the intense Nazi air raids that tried to cripple England's manufacturing ability.

This is the home of heavy metal. Not that heavy metal -- at least not yet -- but the kind from which cars and girders and soup cans are built. A young welder named Tony Iommi works in one of Birmingham's many factories, but he aspires to greater things; the kid is a solid guitarist.

He quits the factory gig at age 17. On his last day of work, the person who works the sheet metal press doesn't show up. Tony the welder is Tony the press worker for the day, no training, no experience.

A big chunk of raw, heavy sheet metal is a dangerous thing, and sure enough the young guitarist gets bitten. He loses the tips of two fingers to the press. “The bones were sticking out of them. There was blood everywhere. I was so much in shock it didn’t even hurt at first," he says.

At first it looks like his budding career is ruined, but Iommi perseveres. He manufactures crude plastic tips for the middle and ring finger of his fretting hand and looks to the great three-fingered jazz guitarist Django Reinhardt for inspiration. Even with the plastic caps, fretting the strings hurts, so Iommi tunes his guitar down a whole step to ease the tension on the strings.

Fast forward to 1968. Iommi is playing in a band named Mythology with drummer Bill Ward. Ward is a devotee of the great big band drummers: Buddy Rich, Gene Krupa, cats with pockets so deep they can never find the bottom.  Iommi and Ward connect with bassist Geezer Butler and front man Ozzy Osbourne and form Earth, later renamed Black Sabbath.

It all comes together: The bombed out landscape, the clanking factories, the soot and the jazz, all of it mixed up with the drop-tuned guitar, the insanity of their singer, and a very dark -- and very deliberate -- horror vibe. Mix in some serious volume, and that's how that heavy metal was born in England's city of heavy industtrial metal.

Black Sabbath version 1.0 is nearly synonymous with the '70s. Their self-titled debut was released on Friday, Feb. 13, 1970, and Osbourne was fired in April 1979. During that decade the band released eight albums.

Black Sabbath's first eight albums were essential listening for music enthusiasts with no interest in the decade's prevailing trends.

Those eight albums were essential listening for music enthusiasts with no interest in the decade's prevailing trends: disco, the laid back California sound of bands like the Eagles, singer-songwriters of the James Taylor variety. Sabbath was for outsiders, misfits, and miscreants; in other words, future musicians. The seeds sown by the band during the '70s grew into a whole new genre by the late '80s: grunge.

Grunge has many influences, just as heavy metal can count big band, gypsy guitar, and clanging machines among its influences. But Sabbath's impact on Seattle bands is indisputable, particularly on Soundgarden. D-tuning is one of the keys to Kim Thayil's unique sound. Back in 2013 he told Guitar World how that came about:

There was a conversation between me, [Melvins singer and guitarist] Buzz Osborne and [Green River singer and future Mudhoney frontman] Mark Arm in Mark’s apartment in the U District [the University District in Seattle] in ’85 or ’86. We were just sitting around listening to records, and Buzz was telling us about Black Sabbath. He said, “Hey, you know on this song Tony Iommi uses this tuning where he tunes his E string down to D.”

From there the drop-D tuning spread throughout the Seattle scene. Thayil says in the same article that the reason "Alice In Chains and Nirvana started using it was because we used it."

Without Black Sabbath we don't have grunge, at least not as we know it.

And so without Black Sabbath we don't have grunge, at least not as we know it -- and not just grunge but countless alternative bands. Sabbath's DNA is easy to spot in the Rollins Band and Faith No More, too, just to name a couple.

Nobody did it better than Soundgarden, though. Reflecting on the first time he heard 'Black Hole Sun,' head Foo Fighter Dave Grohl told Spin Magazine:

"...I remember thinking, 'Holy s--t, this ... will be enormously huge. Because to me it was that perfect meeting of the Beatles and Black Sabbath, which is I think what we put in our Nirvana bio... But I don't think that had ever successfully been paired until that record, and in particular that song. It was so much more melodically sophisticated than anything any of the other bands in Seattle were doing."

Any fan of alt-indie or grunge needs the first four Sabbath albums in his or her collection, bare minimum. On that note, we'll leave you with a tasty cover of 'War Pigs' from Faith No More:

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