American heavy metal is a genre of rock music that emerged in the late 1960s and early 1970s. It is characterized by loud, distorted guitars, powerful vocals, and aggressive drumming. Bands like Black Sabbath and Metallica played a significant role in shaping the sound and style of heavy metal, influencing countless musicians and subgenres. The genre often explores themes of rebellion, fantasy, and social issues. Over the years, it has diversified into various subgenres, including thrash metal, death metal, and black metal. Heavy metal remains a vital part of American music culture, with a dedicated fan base and numerous festivals celebrating the genre.