Trance is a genre of electronic dance music that developed in the 1990s. Trance music is generally characterized by a tempo of between 120 and 140 BPM, short melodic synthesizer  phrases, and a musical form that builds up and down throughout a track. It is a combination of many forms of music such as industrial, techno, and house. The origin of the term is uncertain, with some suggesting that the term is derived from the Klaus Schulze album Trancefer (1981) or the early trance act Dance 2 Trance. In any case, the name is undoubtedly linked to the ability of music to induce an altered state of consciousness  known as a trance. The effect of some trance music has been likened to the trance-inducing music created by ancient shamanists during long periods of drumming.