the Dutch TV show Niks te gek (translation: "Nothing [is] too crazy"), where mentally disabled people (18 years or older) can get their wishes granted. In the episode, they recorded, together with the autistic Ruurd Woltring, one of his own compositions, "Forevermore". The single was released through Nuclear Blast on 25 September 2012. The band announced on their official website that on March 23, 2013, they would celebrate the 10th anniversary of Epica in Eindhoven, Netherlands. The concert which would be called Retrospect, would be held in Klokgebouw with a 70-piece orchestra, choirs, international guests and many special effects. The band invited the Hungarian Remenyi Ede Chamber Orchestra and the Choir of Miskolc National Theatre to this show as they were the same orchestra that accompanied Epica in the recording of the live album The Classical Conspiracy. The concert consisted of a 70-piece orchestra, special effects, acrobats, guest vocalist Floor Jansen (Nightwish) and former band members Ad Sluijter, Yves Huts and Jeroen Simons. Finnish singer Tarja Turunen was also invited to the show, but had to decline due to scheduling problems. In the show the band introduced a new song titled "Retrospect" and played "Twin Flames" from Requiem for the Indifferent for the first time. They also played for the second time their longest song "The Divine Conspiracy", however a shorter version of this song was played. During the concert, Coen Janssen announced that Retrospect would be filmed for release as a DVD. The Quantum Enigma and Epic Metal Fest (2013–2015) Epica revealed on their official website the first details about their sixth album on February 5, 2014. It was revealed that the new album would be titled The Quantum Enigma and would be released at the beginning of May 2014. Later that same month the band unveiled the album's cover art, which was created by longtime collaborator Stefan Heilemann to accompany the ideas behind the lyrics. Track listing and release dates were announced the same day as well and eventually The Quantum Enigma was released by Nuclear Blast on 2 May (Europe), 5 May (UK) and 13 May (USA). The album was produced by Joost van den Broek and recorded in the Sandlane Recording Facilities in The Netherlands. The Quantum Enigma debuted at 110 on US Billboard 200, making it Epica's second entry on this chart, the previous being Requiem for the Indifferent and charting there in February 2013.