Reykjavík's Sigur Rós are known internationally for their pioneering cosmic post-rock creations. Combining ambient electronics, orchestral and rock instruments, and the mournful falsetto of leader Jónsi, all to varying and slowly shifting degrees, they emerged with the sprawling Von in 1997. A long (ongoing) succession of chart-topping releases in their native Iceland began with their follow-up breakthrough, 1999's Ágætis Byrjun, and their gradual ascent up the charts abroad crested with their sixth album, 2012's Valtari; it reached the Top Ten in the U.S., U.K., Ireland, and ...