In modern popular music, the term "underground" refers to performers or bands ranging from artists that do DIY guerrilla concerts and self-recorded shows to those that are signed to small independent labels. In some musical styles, the term "underground" is used to assert that the content of the music is illegal or controversial, as in the case of early 1990s death metal bands in the US such as Cannibal Corpse for their gory cover art and lyrical themes. Black metal is also an underground form of music and its Norwegian scene are notorious for their association with church burnings, the occult, murders and their Anti-Christian views.