Sigur Ros' celebrated third album, and for many people — especially in U.S. where it remains their biggest selling work — the most quintessentially Sigur Ros record of their career to date. It is the only album where Jonsi sings entirely in the wordless lyrics of Hopelandic, a language created by Jonsi that consists of onomatopoeia and amphibious words. 

This desire to elide meaning and allow the listener to bring their own interpretation to the music extends to the eight songs, all of which are nameless.

The music is broadly split into two halves, divided by a critical 36 seconds of silence. The first half of the album is lighter and more optimistic, the second bleaker and more melancholic, culminating in the thundering climax of Untitled No. 8, the closing song of every Sigur Ros show since the song was written in 2000.