by the late 1960s, a number of different rock music below-genres had come out. these included hybrids like blues rock, folk rock, country rock, and jazz-rock fusion. from these forms, the counterculture developed psychedelic rock. new genres that came from this scene included progressive rock, glam rock and heavy metal. progressive rock made the music more artistic. glam rock focused on showmanship and what you can see. heavy metal focused on loudness, 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 caused other below-genres to come about into the 1980s, including new wave, post-punk and eventually the alternative rock movement. from the 1990s, alternative rock began to be the most popular type of rock music. it broke through into the mainstream in the form of grunge, britpop, and indie rock. more merging of below-genres have since emerged. these include pop punk, rap rock, and rap metal, as well as conscious attempts to revisit rock's history, including the garage rock/post-punk and synthpop revivals at the beginning of the new millennium.