Heavy metal is a genre of rock music characterized by its loud, aggressive sound and powerful instrumentation. It typically features distorted electric guitars, strong bass lines, and emphatic drumming. The lyrics often explore themes of rebellion, fantasy, and social issues, and the genre has produced iconic bands like Metallica, Black Sabbath, and Iron Maiden. Originating in the late 1960s and early 1970s, heavy metal has evolved into various subgenres, including thrash metal, death metal, and power metal. It has a dedicated fan base and has influenced many other music styles, as well as fashion and culture, making it a significant part of the music landscape.