U2's Unforgettable Fire album shows a band finding their mature voice
The Unforgettable Fire, U2's fourth studio album, was recorded in a castle, the magnificent Slane, since used as a concert venue by just about every Western pop and rock megastar alive.

The Unforgettable Fire
U2
Island

However, it's the castle on the album cover, Moydrum, a stately ruin, that gives a better clue as to what's inside: on this album U2 tear down the walls of their previous hard-rock sound with a radical move into ambient, atmospheric territory, the band's biggest change of direction until they grew giant inverted commas around themselves for 1991's Achtung Baby.
The album was a dramatic shift in both music and lyrics from its harder-rocking, anthem-heavy predecessor, War, the band's most political album, featuring the uber-frowny singles Sunday Bloody Sunday and New Year's Day. Bono's more personal, impressionistic lyrics on The Unforgettable Fire came with a more experimental sound, that saw thunderous drums replaced by a subtler shuffle, guitars used to build shifting sonic textures rather than bang-out effects-heavy riffs, and a far looser attitude to structures and arrangements.
The main reason for this was the band's decision to employ the legendary Brian Eno and engineer Daniel Lanois as the album's producers. It was a risky move for a band that had just achieved their first commercial success to work with such an avant-garde figure, and their record company tried to talk them out of it. But Eno awakened U2's experimental side.
While the album aimed to undercut their reputation for firm-jawed, preachy sincerity, that's not to say The Unforgettable Fire isn't a serious effort. U2 hadn't quite discovered their 1990s ironic mode yet, and named the album and one of its songs after an artwork about the atomic bombing of Hiroshima. They also included two songs dealing with Martin Luther King. One of them is Pride (In the Name of Love), by far the album's most commercial and best-known track.