What is Heavy metal music?
{{Infobox Music genre | name = Heavy metal | color = white | bgcolor = crimson | stylistic_origins = {{hlist|[[Hard rock]]|[[Blues rock]]|[[Psychedelic rock]]}} | cultural_origins = Late 1960s [[United Kingdom]] | instruments = {{hlist|[[Electric guitar]]|[[Bass guitar|bass]]|[[Drum kit|drums]]|[[singing|vocals]]}} | popularity = Worldwide | derivatives = | subgenrelist = :Category:Heavy metal | subgenres = {{hlist|[[Black metal]]|[[death metal]]|[[doom metal]]|[[folk metal]]|[[glam metal]]|[[gothic metal]]|[[power metal]]|[[progressive metal]]|[[speed metal]]|[[symphonic metal]]|[[thrash metal]]|[[viking metal]]}} | fusiongenres = {{hlist|Deathcore|[[grindcore]]|[[metalcore]]|[[nu metal]]}} | regional_scenes = | other_topics = [[Rock music]] }} '''Heavy metal''' is a loud, aggressive style of [[rock music]]. The [[band]]s who play heavy metal music usually have one or two [[guitar]]s, a [[bass guitar]] and [[drum]]s. In some bands, electronic [[Keyboard instrument|keyboards]], organs, or other [[musical instrument|instruments]] are used. Heavy metal songs are loud and powerful-sounding, and have strong rhythms that are repeated. There are many different types of heavy metal, some of which are described below. Common features of heavy metal include slackened (downtuned) instruments and unusual key changes and time signatures (metre). Heavy metal bands sometimes dress in jeans, leather jackets, and leather boots, and have long hair. Heavy metal bands sometimes behave in a dramatic way when they play their instruments or sing. However, many heavy metal bands do not like to do this. == History == === 1960s and 1970s === [[File:Black Sabbath (1970).jpg|thumb|right|Many historians believe that [[Black Sabbath]] invented heavy metal music.]] In the very late 1960s and 1970s, [[rock and roll]] turned into a harder, louder form of music called rock. In the 1970s, [[rock music]] bands played huge, loud concerts in outdoor stadiums. In the