Heavy metal, sometimes referred to as simply metal, is a form of music characterised by aggressive, driving rhythms and highly amplified distorted guitars. Its origins lie in the hard rock bands who between 1967 and 1974 took blues and rock and created a hybrid with a heavy, guitar-and-drums-centered sound.

From the late 1970s on, many bands would fuse this sound with a revival of European classical music. Heavy metal had its peak popularity in the 1980s, during which many of the now existing subgenres first evolved. Although not as commercially successful as it was then, heavy metal still has a large world-wide following of fans known by terms such as metalheads, headbangers and moshers.

Cited from Wikipedia.