"One" is a song by the Irish rock band U2, originally released in 1991. It is written in the key of B major, and is included in their seventh studio album, "Achtung Baby." The song was composed by all four members of the band - Bono, The Edge, Adam Clayton, and Larry Mullen Jr. "One" has a powerful and melodic structure, blending elements of rock and alternative genres. It gained significant commercial success and critical acclaim, becoming one of U2's most recognizable and beloved songs. Fun trivia: the song was initially written as a bitter breakup song, but over time transformed into a more universal message of unity.