Viking metal is a subgenre of heavy metal music characterised by its galloping pace, keyboard-rich anthemic sound, bleakness and dramatic emphasis on Norse mythology, Norse paganism, and the Viking Age.
There is something undeniably cool about the idea of metal about Viking mythology incorporating elements of traditional Scandinavian folk music. At least the abstract idea of it is cool - as an artform - the history of metal in Norway is way more messed up then I thought... some of these guys got into folk religion because Satanism isn't anti-Christian enough, and we're not just talking about philosophy here. There was a epidemic of church arsons associated with the scene in the early 1990's.
The first song is instrumental:
The second is Finnish:
There are some interesting threads that have fallen off from this, such as this Swiss "ambient metal" band whose music is supposed to characterize the emptiness of outer space: