Thrash is a genre of metal that flourished in the 1980s and enjoyed a revival in the 21st century. Thrash of the 1980s was centered mostly in the Bay Area, where bands like Testament and Exodus hailed from. Megadeth and Metallica also hailed from the Bay Area and along with Anthrax and Slayer make up the "Big Four" of classic thrash. Crossover is a sub-genre of thrash which merges thrash and hardcore punk. Crossover thrash bands include Dirty Rotten Imbeciles and Cryptic Slaughter, both of which pushed the boundaries of of hardcore punk's speed and intensity while blurring the lines between punk and metal. Thrash revival bands include Toxic Holocaust and Municipal Waste.
Grindcore is another genre that grew out of interrelations between hardcore punk and heavy metal. Bands like Napalm Death, Fear of God and Sore Throat merged the speed of punk rock with the intensity of heavy metal and a dollop of experimentation to create grindcore. Other early grindcore bands include Carcass, Terrorizer and Godflesh, who are of particularly interest due to their use of drum machines. Grindcore is marked by blast beats, raw, guttural vocals and lyrics that run the gamut from gore and guts to politics and society. Contemporary grindcore bands include Knelt Rote, Superbad, Engorged and Agoraphobic Nosebleed.
Black metal may be more known for its visual presentation--corpse paint, spiked gauntlets and photo shoots outside of castles. Black metal began with the Venom album that gave the genre its name, "Black Metal." Other early black metal bands include Celtic Frost and Mercyful Fate. Black metal is notable for shrieked vocals, very fast guitar riffing, blast beats and strident Satanism. Black metal has two very broad sub-genres: raw black metal (bands such as Dark Funeral and Dark Throne) and the symphonic style (bands like Dimmu Borgir and Emperor).
Death metal burst into popularity in the 1980s largely out of Florida. Notable for growled vocals, lightning-fast guitar riffs and solos and a lyrical fascination with Satanism and (what else?) death. Possessed and Slayer provide examples of early influences, but the scene didn't really find its expression until Death released their seminal album, "Scream Bloody Gore." Death's Floridian contemporaries include death metal legends Morbid Angel and Deicide. Bands from Gothenburg such as Dark Tranquility and In Flames breathed new life into the genre with the sub-genre melodic death metal.
Fans of Black Sabbath will be keenly interested in sludge metal. Sludge blends the slow, dark riffs of the first three Sabbath records with recent developments in death metal, crust punk and stoner rock. Sludge first took off in New Orleans around bands like Eyehategod and Crowbar. The North Carolina scene sprung up next around bands with more of a punk influence than a blues influence like Buzzov*en and late period Corrosion of Conformity. The northwest offered grunge gods and Sabbath worshippers, The Melvins.