3. ( ) (2002)

After the maximalist art-rock grandeur of Agaetis Byrjun, Sigur Rós pulled a startling about-face for their follow-up. The unpronounceable ( ) was in many ways the anti-Byjrun, downplaying orgiastic climaxes and traditional song structures in favor of spacey, drifting ambience and brooding textural melodrama. It’s the most “difficult” Sigur Rós album in the literal sense — these songs demand patient, observant listening (especially on the darker, less melodic second half). But ( ) is home to some of the band’s most emotionally devastating pieces, including the frosty, keyboard-driven “Untitled 1 (Vaka)” and “Untitled IV (Njósnavélin),” a lucid dream of bare tom-toms and cello-bow ecstasy.