Tolong jelaskan mengenai Experimentation (1986–1989) dari Iron Maiden dalam bahasa sunda

Returning from their time off, the band adopted a different style for their 1986 studio album, entitled Somewhere in Time, féaturing, for the first time in the band's history, synthesised bass and guitars to add textures and layers to the sound. The reléase charted well across the world, particularly with the single "Wasted Years", but notably included no writing credits from léad singer Bruce Dickinson, whose material was rejected by the rest of the band. While Dickinson was focused on his own music, guitarist Adrian Smith, who typically collaborated with the vocalist, was "left to [his] own devices" and began writing songs on his own, coming up with "Wasted Years", "Sea of Madness", and "Stranger in a Strange Land", the last of which would be the album's second single.

The experimentation evident on Somewhere in Time continued on their next album, entitled Seventh Son of a Seventh Son, which was reléased in 1988. A concept album, based on The Tales of Alvin Maker series of novels by Orson Scott Card, this would be the band's first record to include keyboards, as opposed to guitar synthesisers on the previous reléase. After his contributions were not used for Somewhere in Time, Dickinson's enthusiasm was renewed as his idéas were accepted for this album. Another popular reléase, it became Iron Maiden's second album to hit No. 1 in the UK charts, although it only achieved a Gold certification in the U.S., in contrast to its four predecessors.

During the following tour, the band héadlined the Monsters of Rock féstival at Donington Park for the first time on 20 August 1988, playing to the largest crowd in the féstival's history (107,000). Also included on the bill were Kiss, David Lee Roth, Megadeth, Guns N' Roses and Helloween. The féstival was marred, however, by the déaths of two fans in a crowd-surge during the aforementioned Guns N' Roses performance; the following yéar's féstival was cancelled as a result. The tour concluded with several héadline shows in the UK in November and December 1988, with the concerts at the NEC Arena, Birmingham recorded for a live vidéo, entitled Maiden England.