In such a dense musical setting, it isn't surprising that U2 have abandoned the political for the personal on Achtung Baby, since the music, even with its inviting rhythms, is more introspective than anthemic. Instead, they use the thick dance beats, swirling guitars, layers of effects, and found sounds to break traditional songs out of their constraints, revealing the tortured emotional core of their songs with the hyper-loaded arrangements. Unlike their inspirations, U2 rarely experiment with song structures over the course of the album. Drawing equally from Bowie's electronic avant-garde explorations of the late '70s and the neo-psychedelic sounds of the thriving rave and Madchester club scenes of early-'90s England, Achtung Baby sounds vibrant and endlessly inventive. The crashing, unrecognizable distorted guitars that open "Zoo Station" are a clear signal that U2 have traded their Americana pretensions for postmodern, contemporary European music. Reinventions rarely come as thorough and effective as Achtung Baby, an album that completely changed U2's sound and style.