Experimentation (1986–1989)

Returning from their vacation, the band adopted a different style for their 1986 studio album, entitled Somewhere in Time. This was not a concept album, though it was themed loosely around the idea of time travel and associated themes - history, the passage of time, and long journeys. It featured, for the first time in the band's history, synthesised bass and guitars to add textures and layers to the sound. Though considered different from the norm of Maiden sounds, it charted well across the world, especially with the single "Wasted Years".

The experimentation evident on Somewhere in Time continued and was apparent on their next album, entitled Seventh Son of a Seventh Son, which was released in 1988. Adding to Iron Maiden's experimentation, it was a concept album featuring a story about a mythical child who possessed clairvoyant powers. For the first time, the band used keyboards on a recording, as opposed to guitar synthesisers on the previous release. Critics claimed this produced a more accessible release. It became the band's second album to hit #1 in the UK charts. During the Donington Park Festival on August 20, 1988, attendance was placed as 107,000; the biggest crowd attendance in the festival's history. Other performances in the festival include Kiss, David Lee Roth, Megadeth, Guns N' Roses and Helloween.

In 1990, to end Iron Maiden's first ten years of releasing singles, they released The First Ten Years, a series of ten CDs and double 12" vinyls. Between 24 February and 28 April 1990, the individual parts were released one-by-one, each containing two of Iron Maiden's singles, including the B-sides.