This is a list of rock music genres consisting of subgenres of popular music that have roots in 1940s' and 1950s' rock and roll, and which developed into a distinct identity as rock music in the 1960s, particularly in the United Kingdom and the United States. By the late 1960s, a number of identifiable rock music subgenres had emerged, including hybrids like blues rock, folk rock, country rock, and jazz-rock fusion, many of which contributed to the development of psychedelic rock influenced by the counter-cultural psychedelic scene. New genres that emerged from this scene included progressive rock, which extended the artistic elements; glam rock, which highlighted showmanship and visual style; and the diverse and enduring major subgenre of heavy metal, which emphasized volume, power, and speed. In the second half of the 1970s, punk rock both intensified and reacted against some of these trends to produce a raw, energetic form of music characterized by overt political and social critiques. Punk was an influence into the 1980s on the subsequent development of other subgenres, including new wave, post-punk and eventually the alternative rock movement. From the 1990s alternative rock began to dominate rock music and break through into the mainstream in the form of grunge, Britpop, and indie rock. Further fusion subgenres have since emerged as well as conscious attempts to revisit rock's history.