Heavy metal music

Heavy metal (sometimes referred to simply as metal) is a genre of rock music that developed between 1969 and 1974. With roots in blues-rock and psychedelic rock, the bands that created heavy metal developed a thick, heavy, guitar-and-drums-centered sound, characterised by the use of highly-amplified distortion and fast guitar solos. Allmusic declares, "Of all rock & roll's myriad forms, heavy metal is the most extreme in terms of volume, machismo, and theatricality."

Throughout its history heavy metal has had a large world-wide following of fans known by terms such as "metalheads" and "headbangers". Early heavy metal bands Led Zeppelin and Black Sabbath were popular but critically reviled at the time, a trend that has been present throughout the history of metal. As the original wave of heavy metal bands began to wane, the late 1970s brought the New Wave of British Heavy Metal which stripped away much of the music's blues influence instead fusing it with punk rock innovations and some of its aesthetic. Heavy metal became extremely popular in the 1980s, at which time many of the now existing subgenres first evolved. Some subgenres, often more aggressive and extreme than metal music of the past, were often restricted to underground audiences, but some like glam metal and to a lesser extent thrash metal were able to gain mainstream commercial success. In recent years subgenres like nu metal have broadened the scope of what is considered heavy metal while much of the metal music of the past is being critically reevaluated.