Although the concept itself has been growing in popularity since the late 20th century, the exploration of regional folk traditions by European heavy metal bands really blossomed into a significant, stand-alone subgenre during the first decade of the new millennium, yielding unorthodox groups and sounds ranging from Ireland's Cruachan, to Switzerland's Eluveitie, to Germany's Equilibrium. But it's in Scandinavia that folk-metal has probably spawned the largest number of bands, including Finnish entries like Amorphis and Finntroll, and Norwegians Windir and Lumsk. Originally fo...