Alternative rock is a category of rock music that evolved from the independent music underground of the 1970s. Alternative rock acts achieved mainstream success in the 1990s with the likes of the grunge, shoegaze, and Britpop subgenres in the United States and United Kingdom, respectively. During this period, many record labels were looking for "alternatives", as many corporate rock, hard rock, and glam metal acts from the 1980s were beginning to grow stale throughout the music industry. The emergence of Generation X as a cultural force in the 1990s also contributed greatly to the rise of alternative rock.