Undertow is the first full-length studio album by American progressive metal band Tool, released in 1993. According to Allmusic, Undertow helped heavy metal music and progressive rock remain prominent as a mainstream musical style, and allowed several later bands to break through to the mainstream. It was released at a time when grunge was at the height of its popularity, and pop punk was slowly beginning to gather mainstream attention. AllMusic saw the album's success in the "striking, haunting visuals that complemented the album's nihilistic yet wistful mood." As of July 7, 2010, Undertow has sold 2,910,000 copies in the US and been certified 2x Platinum by the RIAA.