Birmingham doom pioneers BLACK SABBATH released their third studio album "Master of Reality" on July 21st, 1971, through Vertigo Records. Following the darker turn of "Paranoid," the record pushed even heavier, with Tony Iommi tuning his guitar down three semitones to C# — a decision born from workplace-accident nerve damage in his fretting hand that inadvertently invented the low, crushing tone future doom and stoner metal bands would chase for decades. Opener "Sweet Leaf" built around a coughing sample announced the band's cannabis fixation, while "Children of the Grave" and "Into the Void" delivered apocalyptic riffing over Geezer Butler's bleak, war-haunted lyrics. Ozzy Osbourne's mournful acoustic interlude "Solitude" showed unexpected range. Reaching the UK and US top ten, "Master of Reality" is now widely regarded as the blueprint for doom metal, cementing BLACK SABBATH's role as heavy metal's founding architects.

Canadian multi-instrumentalist Devin Townsend released "Ocean Machine: Biomech" — originally credited to the moniker Ocean Machine — on July 21st, 1997, via his own newly founded HevyDevy Records. Written partly during his stint as touring vocalist for guitarist Steve Vai's "Sex & Religion" band, the sprawling album fused death growls, symphonic keyboard layers, choral harmonies, and progressive metal riffing into a meditative concept work exploring isolation, depression, and nature, shaped by Townsend's rural British Columbia upbringing. Unable to secure label backing, Townsend self-released the record, pressing his independent label into existence almost by necessity. Musically it departed sharply from the extreme aggression of his other band STRAPPING YOUNG LAD, drawing comparisons to Pink Floyd's sense of escapism. Though a modest seller initially, "Ocean Machine: Biomech" grew into a beloved cult classic and the clearest blueprint for the layered, maximalist "wall of sound" that would define Townsend's celebrated solo career.

New York thrash veterans ANTHRAX released their eighth studio album "Volume 8: The Threat Is Real" on July 21st, 1998, through Ignition Records. The record marked a stylistic pivot toward a groovier, more modern metal sound as the band adapted to the post-grunge landscape while retaining vocalist John Bush, whose muscular delivery anchored tracks like "Inside Out" and "Killing Box." Guitarists Scott Ian and Rob Caggiano — the latter making his ANTHRAX debut — traded thrash-era speed for chunkier, mid-tempo riffing, drawing comparisons to PANTERA and contemporary alternative metal. Commercially, the album underperformed compared to ANTHRAX's late-1980s peak, reflecting the era's difficult climate for veteran thrash acts. Despite mixed reception at release, "Volume 8" has since been reappraised by fans as an underrated chapter in the band's catalog, showcasing Bush-era ANTHRAX at its heaviest and most focused.

Los Angeles Christian metal pioneers STRYPER released their debut EP "The Yellow and Black Attack" on July 21st, 1984, through Enigma Records. Fronted by brothers Michael and Robert Sweet alongside guitarist Oz Fox and bassist Tim Gaines, the band paired glam metal's flash — spandex, hairspray, and their signature yellow-and-black bee-striped stage gear — with explicitly evangelical Christian lyrics, a combination unheard of on the Sunset Strip scene. Enigma pressed fewer than 20,000 copies initially, unsure whether a Christian metal act could find an audience, but tracks like "Loud N' Clear" and a cover of "Reason for the Season" built a devoted following through relentless touring and Bible-verse-flinging concerts. The EP's surprise success led to a full-length deal and STRYPER's eventual platinum-selling breakthrough. "The Yellow and Black Attack" remains the foundational document of Christian metal as a viable commercial subgenre.

Japanese heavy metal pioneers LOUDNESS released their second studio album "Devil Soldier" (戦慄の奇蹟) on July 21st, 1982, through Nippon Columbia. Formed by guitarist Akira Takasaki and drummer Munetaka Higuchi from the ashes of Lazy, LOUDNESS paired Takasaki's blistering neoclassical-tinged lead work with vocalist Minoru Niihara's soaring range and bassist Masayoshi Yamashita's driving low end. "Devil Soldier" pushed the band's sound into darker, harder territory than their debut, embracing occult-tinged imagery and galloping tempos indebted to the New Wave of British Heavy Metal while retaining a distinctly Japanese melodic sensibility. The album won Best Heavy Metal Album at Japan's music awards that year, cementing LOUDNESS as the country's preeminent metal export years before their English-language breakthrough with "Thunder in the East." "Devil Soldier" remains a foundational text for Japanese metal, showcasing the technical ambition that would define the genre's homegrown scene.

Guitarist James "Big Jim" Martin, best known for his tenure in Bay Area alternative metal pioneers FAITH NO MORE, was born on July 21st, 1961, in Oakland, California. Joining the band in 1983, Martin's crunching, riff-driven guitar work became a defining pillar of FAITH NO MORE's sound across four studio albums, from the raw "We Care a Lot" and "Introduce Yourself" through the band's commercial breakthrough "The Real Thing" in 1989, which paired his metal muscle with Mike Patton's newly arrived vocals on hits like "Epic." Martin's contribution deepened on the sprawling, genre-scrambling "Angel Dust" in 1992, widely considered a landmark of alternative and funk metal. Tensions over the band's increasingly experimental direction led to his firing by fax in late 1993. Martin later toured with punk band Fang and briefly reunited onstage with METALLICA, but remains best remembered for anchoring one of alternative metal's most influential guitar tones.

Canadian progressive thrash innovators VOIVOD released "Morgöth Tales" on July 21st, 2023, through Century Media Records, marking the 40th anniversary of the band's formation in Jonquière, Quebec. Rather than a new collection of original material, the album gathered freshly re-recorded versions of nine classic tracks spanning the band's 1984-2003 catalog, performed by the current lineup of guitarist Daniel "Chewy" Mongrain, bassist Dominique "Rocky" Laroche, and drummer Michel "Away" Langevin, alongside a brand-new title track. The record featured guest appearances from former members Eric Forrest and Jason Newsted, bridging multiple eras of the band's shapeshifting, sci-fi-obsessed history. Known for pioneering angular, dissonant riffing that influenced generations of progressive and technical metal bands, VOIVOD used "Morgöth Tales" to honor its own legacy while reintroducing longtime staples like "Killing Technology" and "Thrashing Rage" to a new generation of listeners.

Justin Lowe, founding guitarist of Minnesota deathcore band AFTER THE BURIAL, was found dead on July 21st, 2015, at age 32, having fallen from the Soo Line High Bridge near Somerset, Wisconsin. Born in Flemington, New Jersey, Lowe co-founded the band in 2004 and contributed intricate, technically demanding riffs across the albums "Forging a Future Self," "Rareform," "In Dreams," and "Wolves Within," helping define the syncopated, djent-inflected deathcore sound alongside contemporaries like THE BLACK DAHLIA MURDER within the Twin Cities metal scene. Just weeks before his death, Lowe had abruptly left AFTER THE BURIAL, posting an unsettling statement accusing bandmates, the label, and others close to him of conspiring against him. His passing shocked the technical metal community, prompting tributes from musicians who cited his precise, mathematically complex playing as formative to the genre. AFTER THE BURIAL continued on, but Lowe's intricate guitar work remains a touchstone for deathcore players.

Canadian singer Lee Aaron, born Karen Lynn Greening on July 21st, 1962, in Belleville, Ontario, rose to fame in the early 1980s as one of heavy metal's rare prominent female frontwomen, earning the nickname "Metal Queen." Her breakthrough came with the 1984 album "Metal Queen," whose title track and imagery cemented her as a genuine heavy metal figure in an era dominated almost entirely by men, leading to a multi-album deal with Attic Records and a lasting songwriting partnership with guitarist John Albani. Follow-up releases "Call of the Wild" (1985) and the self-titled "Lee Aaron" (1987) further built her reputation for powerful, soaring vocals over driving riffs. Her 1989 album "Bodyrock" sold over 200,000 copies in Canada on the strength of hits like "Whatcha Do to My Body." Though she later moved toward pop, alt-rock, and jazz, Aaron remains celebrated as a pioneering woman in heavy metal's history.

English extreme metal outfit AKERCOCKE released the live album "Decades of Devil Worship" on July 21st, 2023, through Peaceville Records, capturing a 2007 performance at London's Underworld venue. Known for fusing black metal, death metal, and jazz-inflected progressive passages with openly Satanic and occult lyrical themes, AKERCOCKE built a devoted cult following throughout the 2000s on albums like "Rape of the Bastard Nazarene" and "The Goat of Mendes," both heavily represented in this set's tracklist. The recording captures founding members Jason Mendonça and David Gray at a creative peak, before the band's extended hiatus later that decade and eventual 2016 reformation. Released to mark the band's ongoing legacy in the UK extreme metal scene, "Decades of Devil Worship" offered longtime fans a rare document of AKERCOCKE's ferocious live show, preserving a snapshot of one of British extreme metal's most theatrically transgressive acts at full power.