Doom metal is a form of heavy metal music that emerged as a recognized sub-genre during the first half of the 1980s. Generally, doom metal features very slow tempos, low-tuned guitars and a much "denser" or "heavier" sound than other metal genres. Both the music and the lyrics intend to evoke a sense of dread or impending doom, and often an atmosphere of despair. Musically, doom metal is strongly influenced by the early work of Black Sabbath. A number of their early songs, such as "Black Sabbath" and "Into the Void" are considered embryonic or prototypical doom metal songs.