Punk rock is a genre of popular music characterised by a fast tempo, distorted guitars, aggression and relatively simplistic musical structures. It began in the 1970s, partly as a reaction to progressive rock groups who favoured musical complexity for its own sake over conveying emotions. By contrast, punk rock was extremely accessible: lack of musical ability was sometimes seen as a strength, meaning that anyone who wanted to could form a punk band. Successful bands from the early days of punk include the Sex Pistols, the Buzzcocks and the Damned.
In later years, punk has fractured into numerous sub-genres including hardcore, street punk, pop-punk, ska-punk and many others. There is some debate as to what constitutes 'true' punk music, since many groups that are considered to be punk are replicating the musical style of previous punk groups in an era when this style is no longer seen as anti-establishment, which other punks see as contrary to the 'outsider' ethos of the movement. In essence, this disagreement hinges on whether punk is to be characterised by musical forms or by attitude and intent.
As well as music, the punk movement had a strong fashion element, with adherents favouring outlandish hairdos, tattered rags or even bin-liners in place of clothes, and heavy, military-style footwear.