Are Iceland's Sigur Rós the saviors of 21st-century rock or true heirs to the silk-robed-and-platform-booted, pompous progressive rock of the '70s? On their third album (first for a major label), they are a little bit of both. The group continues to mix the most interesting aspects of U2 (the anthem), Low (the maximalist slow-mo thing), Radiohead (the utter lack of irony in the quest to make meaningful art for stadium crowds), and My Bloody Valentine (guitar as texture), while not sounding like anyone else on this planet. The average song length on the eight untitled tracks is eight minutes, with cascades of moaning, bowed guitars colliding with low-end keyboards while the lovely, alien-registered vocals of singer Jónsi float on top. Dynamics are employed spectacularly, but half of the album is spooky soundtrack music that never really goes anywhere. However, the actual songs on