Dream Theater started the Octavarium Tour extensively throughout 2005 and 2006 to celebrate their 20th Anniversary as a band, including a headlining spot on Gigantour alongside Megadeth and put together by frontman Dave Mustaine, also featuring Fear Factory, Nevermore and Symphony X. During a show on August 2, 2005, in Dallas, the band paid tribute to Pantera's late guitarist Dimebag Darrell by performing the song "Cemetery Gates" as an encore. In addition was the unexpected appearance of fellow musicians Russell Allen (Symphony X vocalist), Burton C. Bell (Fear Factory vocalist) and Dave Mustaine (Megadeth vocalist/guitarist), who joined the band on stage to perform parts of the song.
Dream Theater started the Octavarium Tour extensively throughout 2005 and 2006 to celebrate their 20th Anniversary as a band, including a headlining spot on Gigantour alongside Megadeth and put together by frontman Dave Mustaine, also featuring Fear Factory, Nevermore and Symphony X. During a show on August 2, 2005, in Dallas, the band paid tribute to Pantera's late guitarist Dimebag Darrell by performing the song "Cemetery Gates" as an encore. In addition was the unexpected appearance of fellow musicians Russell Allen (Symphony X vocalist), Burton C. Bell (Fear Factory vocalist) and Dave Mustaine (Megadeth vocalist/guitarist), who joined the band on stage to perform parts of the song