Rock music is a broad genre that encompasses many subgenres. Two of the most popular subgenres are METAL and emo. METAL is characterized by its heavy sound, distorted guitars, and aggressive lyrics. It originated in the 1970s and has since become one of the most popular genres of rock music. Emo, on the other hand, is a more emotionally charged style of rock music that emerged in the 1990s. It is characterized by its introspective lyrics and melodic sound. Both METAL and emo have been influential in the rock music scene and have helped shape the genre as a whole.