metal." To celebrate their 20th anniversary, Opeth performed a six-show, worldwide tour called Evolution XX: An Opeth Anthology, from 30 March through 9 April 2010. Blackwater Park was performed in its entirety, along with several songs never before performed. The concert of 5 April 2010, at the Royal Albert Hall in London, England was filmed for a DVD and live album package titled In Live Concert at the Royal Albert Hall. The set was released on 21 September 2010, in 2-DVD and 2-DVD/3-CD configurations. For the DVD the concert was split into two sets. The first set consists of the entire Blackwater Park album, while the second set contains one song from every album excluding Blackwater Park, in chronological order representing the twenty years of "evolution" in their music. Åkerfeldt stated, "I can't believe it, but, fuck, we're celebrating 20 years. I've been in this band ever since I was 16. It's insane." A special edition of Blackwater Park was released in March 2010 to coincide with the tour. Heritage (2011–2013) In September 2010, Mikael Åkerfeldt stated that he was writing for a new Opeth album. The band announced on their website that they would start recording their tenth album on 31 January 2011, at the Atlantis/Metronome studios in Stockholm, once again with Jens Bogren (engineering) and Steven Wilson from Porcupine Tree as co-producer. Shortly after mixing was complete on the new album in April 2011, Opeth announced that Per Wiberg was relieved of his duties in the band. In the press statement, Mikael Åkerfeldt explained the decision, saying, "Mendez, Axe and Fredrik and I came to the decision that we should find a replacement for Per right after the recordings of the new album, and this came as no surprise to Per. He had, in turn, been thinking about leaving, so you could say it was a mutual decision. There's no bad blood, just a relationship that came to an end, and that's that." Opeth's tenth album, Heritage, was released on 14 September 2011, to generally favorable reviews. The album sold 19,000 copies in the United States in its first week of release and debuted at number 19 on the Billboard 200 chart. Heritage debuted at number four in the band's native country of Sweden. Heritage became the second Opeth album to not feature any death growls and had a much more progressive style than previous albums from the