Within Temptation is a Dutch symphonic metal band founded in April 1996 by vocalist Sharon den Adel and guitarist Robert Westerholt. They have always been classified by critics as gothic metal, although the "gothic" influence varies with each album. Their most prominent and well-known sound is described as symphonic metal, although their earlier material, such as debut album Enter, was mostly gothic metal, with Enter also having a hint of doom metal. In an interview, den Adel said they fell into a symphonic rock genre with various influences. In a later interview with Dutch music platform 3VOOR12, den Adel stated that "we consider ourselves more a symphonic rock band ... in my opinion, we are no gothic band".After the release of their debut album Enter in 1997, the band became prominent in the Dutch underground scene. It was not until 2001 that they became known to the general public, with the single "Ice Queen" from their second album Mother Earth, which reached No. 2 on the Dutch charts. This was followed by the band winning the Conamus Exportprijs, a Dutch music award, four years in a row, and a fifth in 2016. Their next albums The Silent Force (2004) and The Heart of Everything (2007) debuted at No. 1 on the Dutch charts. In 2008, they released a live DVD and CD, Black Symphony, recorded with the Metropole Orchestra. This was followed in 2009 by An Acoustic Night at the Theatre, another live album.The band's fifth studio album, The Unforgiving, was released in March 2011, alongside both a comic book series and a series of short films that together encompass a story. The first single, "Faster", was released on January 21, and the first short film, Mother Maiden, was released on January 31. The band has sold more than 3.5 million copies of the album worldwide.Their sixth studio album, Hydra, was released in early 2014 in Japan, Europe, and the United States. The album features guest appearances from various artists: Finnish singer Tarja Turunen, who appears in the lead single "Paradise (What About Us?)"; Howard Jones, former vocalist of American metalcore band Killswitch Engage; Dave Pirner, lead vocalist of American alternative rock band Soul Asylum; and American rapper Xzibit. The band had extensive airplay on BBC Radio 2 in the United Kingdom with one of the songs from the album, "Whole World Is Watching" featuring Pirner.