Heavy metal reached the end of the 1990s as a radically different genre from the one that had entered the decade. Thrash and traditional metal no longer controlled the mainstream, but both remained alive beneath the surface. Nu metal was becoming a commercial force while progressive, black and melodic death metal reached remarkable new levels of ambition.

Dream Theater delivered one of progressive metal’s defining concept albums with Metropolis Pt. 2: Scenes from a Memory. The story expanded upon “Metropolis—Part I” from 1992’s Images and Words, following a man named Nicholas as he uncovers memories of a past life involving love, betrayal and murder. The album was Dream Theater’s first with keyboardist Jordan Rudess, completing the lineup that would carry the band into the new millennium. “Overture 1928,” “Home,” “The Dance of Eternity” and “The Spirit Carries On” balanced technical skill with memorable storytelling.

Opeth’s Still Life was another ambitious concept album, but its story unfolded in a much darker world. Mikael Åkerfeldt combined progressive rock, acoustic passages and death metal while telling the tale of an exiled man returning to a religious community for the woman he loves. The album introduced bassist Martin Méndez and included future Opeth classics such as “The Moor,” “Godhead’s Lament,” “Face of Melinda” and “Serenity Painted Death.”

Norwegian black metal continued moving beyond its earliest limitations. Immortal’s At the Heart of Winter introduced longer compositions, clearer production and a powerful black-metal and thrash-metal combination. With Demonaz unable to continue playing guitar because of tendinitis, Abbath handled guitar, bass and vocals alongside drummer Horgh. The change produced one of Immortal’s most focused and influential albums.

Behemoth underwent an equally important transformation on Satanica. The Polish band moved away from its earlier traditional black-metal sound and embraced the muscular blackened death metal that would define its future. Songs such as “Decade of Therion” and “Chant for Eschaton 2000” announced the arrival of a heavier and more commanding Behemoth.

In America, Slipknot’s self-titled Roadrunner debut brought nine masked musicians from Iowa into the centre of heavy music. Producer Ross Robinson captured the band’s mixture of nu metal, death-metal aggression, hip-hop textures and additional percussion. “Wait and Bleed,” “Spit It Out,” “Surfacing” and “(sic)” made Slipknot one of the most talked-about new bands of the year, while its chaotic Ozzfest performances built a rapidly growing following.

Static-X offered a more mechanical take on the changing mainstream with Wisconsin Death Trip. Wayne Static called the sound “evil disco,” an appropriate description for the album’s combination of industrial programming, danceable rhythms and heavily down-tuned guitars. “Push It,” “I’m with Stupid” and “Bled for Days” became club and concert favourites.

Veteran thrash bands also demonstrated renewed strength. Testament assembled an extraordinary lineup for The Gathering, featuring Dave Lombardo on drums, Steve Di Giorgio on bass and James Murphy on lead guitar. “D.N.R.,” “Down for Life” and “Three Days in Darkness” combined thrash metal with death-metal weight, producing the band’s most aggressive album in years.

Nevermore explored psychological darkness on Dreaming Neon Black. Warrel Dane, Jeff Loomis and the band created a concept album about a man losing his grip on reality after the disappearance of someone close to him. Progressive structures, thrash riffs and Dane’s emotional performance made the record one of Nevermore’s defining achievements.

Sweden remained central to melodic death metal. In Flames released Colony, bringing a cleaner and more accessible production to the Gothenburg sound without abandoning its aggression. Arch Enemy’s Burning Bridges paired Michael and Christopher Amott’s twin-guitar melodies with Johan Liiva’s harsh vocals. It became Liiva’s final studio album with the band before the arrival of Angela Gossow.

Beyond the Top 10, Neurosis released Times of Grace, The Dillinger Escape Plan rewrote the rules of technical hardcore with Calculating Infinity, and Children of Bodom delivered Hatebreeder. Emperor, Dark Tranquillity, Amorphis, Cannibal Corpse, Agalloch, Rage Against the Machine and Gamma Ray added further variety. Metal entered the new millennium divided into countless scenes—but its creative possibilities had rarely seemed greater.