Nightwish is a Finnish symphonic power metal band formed in 1996 in the town of Kitee. Nightwish is considered one of the bands responsible for the rise in popularity of symphonic metal at the end of the 1990s.[1] The band is best known for their international hits "Nemo", "Wish I Had an Angel" and "Sleeping Sun".
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Musical style
A precise definition for Nightwish's musical style is disputed. The band has been suggested as being part of the genres gothic metal, symphonic metal, power metal and gothic rock. Tuomas Holopainen once described their music as "melodic heavy metal with a female vocalist".[22]

genres gothic metal,
symphonic metal,
power metal,
gothic rock,

http://en.wikipedia.org/wiki/Nightwish