Critics don’t quite know what to say about Sigur Rós. Those who like them either go over the top with praise, calling them the best band of the new millennium, get pretentiously creative, writing about flashes of light and angels and the like, or quickly sum them up with a label like “post-rock” or “ambient rock.”

Yet as easy as it is to criticize the critics, I’m not sure what to say about Sigur Rós either. Their music mystifies me. The first time I heard one of their songs, I thought it was a woman fronting a mini-orchestra, with strings and woodwind players. Then I saw a picture of them; they’re four guys who look like hundreds of other rock bands.

As foolish as it seems to say that any music is 100 percent new, I’ve never heard anything like this before. Apparantly Sigur Rós is hugely successful in their native Iceland, which gives me another reason to love Iceland. They’re vaguely in the same vein as other musicians who’ve tried to create an atmosphere of dreaminess, from the shoegazers to the most recent wave of blissed-out ambient and electronic artists. They have the sense of space, environment and knowledge of how disparate sounds interact that the best ambient musicians have; yet, at other times, they sound like a Radiohead-inspired rock band. Their second album Agætis Byrjun, the first available in North America, is filled with gorgeous mystery. No labels or descriptions can begin to tell the whole story.

The highest compliment I can pay Sigur Rós is that their music surprises me at every moment. Instruments continually arrive mid-song just to catch me off guard: Wait, is that a violin? A flute? A steel guitar? The first time I listened to the album straight through, I found myself dropping my jaw in awe, no kidding, at some point during nearly every track. “Sven-g-englar” changes from a pretty pop tune with ambient background noises (like an imitated sonar tone) into a full-on rock song. “Viorar Vel Til Loftarasa” is a soulful ballad mixed with a scary rock tune, until it ends with what sounds like the world exploding.

Another amazing fact is how this music transcends any cultural barrier. Every song is sung in a language foreign to me, either Icelandic or a language the band made up called “Hopelandish,” yet each song delivers powerful emotions. Perhaps that’s the true test of a vocalist’s strength: how well he or she can deliver feelings across a language divide. Lead singer Jon Thor Birgisson’s voice is not only expressive, but unique; many of the songs are sung in a wonderfully weird falsetto.

Sigur Rós’ Agætis Byrjun is a great test to use on jaded critics who claim that there’s nothing new under the sun. Anyone who says they’ve heard music like this before is lying, plain and simple.