In recent months, U2 seemingly turned it focus toward nostalgia by staging a tour that honored the legacy of its 1987 album The Joshua Tree. Yet those who saw the concerts know the band didn't use the trek solely as an opportunity to look back, as the group framed the older songs against modern imagery. And now, with Songs of Experience, released this week, U2 aims again to capture the cultural pulse. The record was delayed, said leader Bono, to overhaul some songs to better reflect today's tense, divisive climate. Yet Songs of Experience isn't an out-and-out political album, and may in fact be U2's most optimistic work. Its songs shoot for resiliency in a time of crisis. (One exception may be the grave "The Blackout," which plays like a warning for everyone to wake up to the realities around them.) It all shows U2's members continue to respond to the world around them and provides us a great excuse to look back at five of our favorite curiosities from the quartet's catalog.

"Hold Me, Thrill Me, Kiss Me, Kill Me"
One can argue the best moment in Batman Forever, the first of two Caped Crusader flicks directed by Joel Schumacher, arrives during the end credits – in part because the poorly received film has come to an end, but also because the sound of U2's "Hold Me, Thrill Me, Kiss Me, Kill Me" makes it one of the more electrifying moments. The Edge's guitar opens the song with a riff that spins around like a helicopter blade. Hitting like an alarm, the guitar gets soon joined by an aggressive rhythm from Larry Mullen Jr. and a mash-up of electronic and symphonic sounds. It's chaos at its most refined, the sound of a band harnessing a frenetic urban energy. Synths, riffs, and Bono's muffled vocals rush by like neon-lit traffic. "You're a headache, in a suitcase," he sings, a barbed line that comes fast on a track on which U2 shows no interest in slowing down.

"I'll Go Crazy If I Don't Go Crazy Tonight" (Remix)
One criticism of modern-day U2 claims the band has lost some of the adventurous, genre-hopping spirit it once possessed. Recent albums focus more narrowly on the band's arena-sized rock arrangements. A very notable exception can be found on the single for No Line on the Horizon's "I'll Go Crazy If I Don't Go Crazy Tonight," which contains a disco and house-centric take courtesy of the DJ Redanka. U2 seemed pretty enamored as well. This is the version of the song the band used on its 360 Tour. And with good reason. The ebb and flow of the brightly shaded dance beats capture the excitement of the infatuation Bono sings about, and the Edge's guitar almost feels like liquid. Rather than the slow-moving, ballad-like version of the song on record, Redanka's reworking sparks with a nervous, excited pulse.

"Numb"
"Numb" served as the lead single of 1993's striking Zooropa, an album recorded over a span of just two months and one that dismantled everything listeners expect about U2. The track still stands as one of U2's most unexpected and mysterious songs. Its sounds are nearly indefinable. While an earthquake rumble of a bass forms the foundation, fuzzy and spiked guitar drives the work forward. Or maybe it's not a guitar. It could be a kitchen utensil, or something more otherworldly, like a ray gun. It doesn't sound like anything we've heard before, and neither do the vocals. The Edge takes the lead. He doesn't sing so much as intone: "Don't answer. Don't ask. Don't try and make sense." Guidelines for living? Or just plain stress? "Numb" doesn't provide answers, but it still feels urgent, and still sounds alien.

"If You Wear That Velvet Dress"
With 1997's Pop, U2 again flexed its experimental muscle, creating an album that went dark when the quartet had often gone light. Audiences weren't so keen, and in 2000, the band returned to its more traditional brand of hearty rock n' roll. Perhaps a shame, as U2 ever since has appeared gun-shy to take its sound into unforeseen realms. So dig up "If You Wear That Velvet Dress," a film-noir sonic experience both devilish and seductive. It's the rare U2 cut where Bono assumes more of an antagonistic character, telling the object of his desire that "I never listened to you anyway." Rough, but Adam Clayton's lascivious bass and Mullen Jr.'s brushed rhythms create a hypnotically romantic mood. And yet the harp-like guitar makes it clear things aren't completely normal, hinting that no one in this tuneful universe has good intentions in mind.

"The Wanderer"
Another cut from Zooropa, an album that only proves better with age thanks to its playfulness, curiosity, and willingness to explore assorted styles and instrumentation without fear of embarrassment. For evidence, tune into "The Wanderer," anchored by the brilliantly textured voice of Johnny Cash. Clayton's bass adopts a bit of a country strut, but sounds of nothing born in Nashville. It's more cartoon-like, a joyfully elastic groove that absorbs the restless spirit of the lyrics. Slightly soulful backing harmonies guide Cash and give the tune a dreamy lilt. Above all else, the song illustrates that U2, no matter where it takes its musical inquisitiveness, expects a winning melody to come with it.

Photo credit: Anton Corbijn