I remember when Apocalyptica, then consisting of four cellists, came out of Finland in the 1990s covering Metallica songs. It was interesting but seemed like a gimmicky, one-and-done sort of thing. I did not follow their career as they expanded their repertoire to include covers of bands such as Faith No More, Sepultura and Pantera. Somewhere along the way, they trimmed the lineup to three cellists, added a drummer, and started writing original songs and bringing in guest vocalists.

It was in fall 2008, a year after the release of Worlds Collide, their sixth studio album, that “I Don’t Care,” featuring Three Days Grace singer Adam Gontier, started burning up the airwaves of rock radio, hitting No. 1 at a time when they were competing with the new songs by heavyweights like AC/DC and, ironically, Metallica. Fans getting into the band through that song have something special waiting for them; Worlds Collide is just short of a symphonic metal masterpiece.

Aside from the hit, most listeners will be drawn initially to songs like “I’m Not Jesus” featuring Slipknot/Stone Sour’s Corey Taylor, “S.O.S. (Anything But Love)” featuring Lacuna Coil’s Cristina Scabbia and “Helden,” a cover of David Bowie’s “Heroes” sung in German by Rammstein’s Till Lindemann. (There’s also “Last Hope” featuring Slayer drummer Dave Lombardo.) But the instrumental tracks are just as good, and it’s cellists Eicca Toppinen, Paavo Lötjönen and Perttu Kivilaako who are the stars. They give Apocalyptica its distinct flavor—heavy, yet achingly beautiful—even on a song as mainstream as “I Don’t Care.”

I think I will be one of many exploring Apocalyptica’s back catalog during the next few months. If it’s half as good as Worlds Collide, we’re in for a treat.