I've lived in Chicago for less than a month, and I've already seen about 600 concerts. That's an exaggeration.

But I have seen quite a few, including Sigur Ros at the Chicago Theatre the other night. (For you anal-retentive types, let's call "the other night" Wednesday, September 21.) I'd never seen them ("them"=group from Iceland known for big, orchestral soundscapes and for singing in Icelandic and a made-up language, Hopelandic) before, but had pretty high expectations based on testimony from trusted sources. I went looking for a complete mind-scoop, and eventually found one. More on that in a minute.

First there was Amina, another Icelandic quartet, known to Sigur Ros fans as the ladies who augment the SR sound with strings. Left to their own devices, they gathered a table full of devices—a laptop, singing wine glasses, cheap Casios, bells, and a bowed saw, among other things—to create utterly charming fairy music. I guess this is no surprise considering they come from a place where everybody believes in water spirits and alternate universes hidden behind rocks (see the pretty good documentary Investigation Into The Invisible World for a look). It was something like live laptronica, but made with absolutely zero sense of irony or distance by four ladies in high-waisted, sorta matronly dresses. Perfect.

Sigur Ros let go some kind of introductory rumble for several minutes before they arrived, and the theater flashed its lights to warn patrons to take their seats. Speaking of the theater, it sold out—something like 3500 tickets—well in advance, which seems amazing to me. They took the stage behind a white screen, flashing shadows and lights and building a mood. And for the first, I dunno, 15 minutes (that'd be about a song and a half), I wasn't terribly impressed. It felt big but sort of empty, like it wasn't exactly connecting the way it should. Then they played "Svefn-g-englar," which might be considered their hit if bands like Sigur Ros had hits, and it clicked from the floor to the ceiling.

(Dramatic paragraph break.) They played for almost two perfectly paced hours, building delicate moments up and then avalanching down on them. The band didn't say a word, either: Jonsi Birgisson just let that creepy, engrossing, beautiful wail act as the emotional cue… And he occasionally bowed his guitar into oblivion. At one point—I think it was during "Hafsol," but I could be way off—a guy in the front row who looked dressed for the office, mid-30s, balding, stood up from his chair because he just couldn't not let it out any more.

During the final pre-encore song ("Smaskifa" — I know this only because the band's publicist sent me a set list), the giant screen behind the band showed silhouettes of birds on a wire; they flew on and off during the song, which ended with everyone leaving the stage except for the drummer, who quietly played a keyboard bit as the birds flew off. It was the perfect ending, and I hoped they'd leave it at that. I was happy they didn't. Instead, they brought out the slow-building "Popplaglid" (a.k.a. the final untitled song from the album with no title, a.k.a. ( )), slowly lowering the screen in front of them and disappearing into a cathartic, intense exhale. I've never seen and heard anything quite like it.

Were you there?