It was a turning point in U2’s career. They had made an experimental album with a visionary producer, something that showed maturation, that suggested whole new avenues their music could explore that few might’ve imagined prior. They had brought a moment-in-history performance to the stage, underlining their expanding reach, the kind that would touch who knows how many people over the decades. Four Irish kids had seen the world, and their ambitions and talents expanded alongside their perception. Now was a time to capitalize — to show what they could do next.

Those were the circumstances that birthed The Joshua Tree, released in March 1987. Partnering with Brian Eno for 1984’s The Unforgettable Fire yielded both their most adventurous album up to that point and the hit single “Pride (In The Name Of Love).” Bono’s infamous venture into the crowd during Live Aid in 1985 had elevated them to rockstar notoriety on an international scale. They had seen countries far outside of the North/South boundaries of Dublin that had once constrained them, and Bono made his life-altering first trip to Africa. The Joshua Tree was the sound of a young band bottling all that up, then letting it flow out into an album that was all-encompassing, universal, classic — the one that began the business of solidifying their place in history.

On March 3rd, 1997 — almost 10 years to the day — the band released Pop.

It had been a strange trip through those 10 years. Partnering with Eno again, and then Flood, U2 had pushed themselves well beyond the original strictures of their personality and aesthetic — first with 1991’s Achtung Baby, even more so with 1993’s Zooropa, and especially on their 1995 one-off collaboration album with Eno under the moniker Passengers. They had staged one of the most ambitious and ludicrous but beloved tours in history with Zoo TV, a live spectacle that dwarfed the moment of forced intimacy at Live Aid. Four Irish kids had grown up, had children, gotten divorced, dated super models, taken drugs in Tokyo, become world-wide celebrities. Once fashioning themselves as punks — an argument half-continued in their attempts to hijack and critique the mainstream while still seeking hits on Achtung Baby and Zooropa — they were now, solidly, pop culture.

Pop was the sound of a band who had been around nearly 20 years but were still just in their mid-30s, bottling all those experiences up into a complicated, flawed, misunderstood album that stands as a divisive oddity in their career while also casting a shadow over everything that followed. Semi-parallels and 10 year arc aside, The Joshua Tree and Pop are linked by their positions in U2’s story. They are brackets around perhaps the most dynamic and debated era of the band’s career, the Big Statement followed by artistic adventurousness that, perhaps, took them too far out to sea, setting the stage for the reset button of 2000’s All That You Can’t Leave Behind and the version of U2 we now know: the classic rock establishment. The Joshua Tree started their ascension in earnest, made them superstars. Pop was the beginning of the fall.

In many ways, Pop was the first big disappointment of U2’s career. Their first several albums were the steady build of an up and coming band. The Joshua Tree was massive. Sure, 1988’s Rattle And Hum was a stumble as far as over-indulgent followups to an artist’s breakthrough go, but it also wasn’t a full-fledged album. The real successor to The Joshua Tree was Achtung Baby — meaning that between their two best, most immortal albums, U2 achieved one of the most effective and total sea changes in rock history. Riding on the popularity of Achtung Baby, U2 were able to pull their fans along through the rest of their experimental ’90s.

Then there was Pop, the album that’s still remembered as U2 pushing further into dance music and incorporating techno influences into their songwriting. The album that felt both overcooked and unfinished, thanks to the band running right up against their deadline for a March ’97 release (already delayed from late ’96) preceding the kickoff of their PopMart Tour. It’s the album accompanied by the tour that the band announced in an appearance at a Manhattan Kmart, next to the lingerie section and under a fake department sign reading “Pop Group” (priced at $U2.97), a tour involving the biggest LED screen ever (at the time), a giant golden arch that coincidentally looked just like half a McDonald’s logo, and that began, naturally, in Las Vegas. (At the Kmart appearance, the band played one song — a b-side called “Holy Joe” that, despite the horrific echo in the live video, is one of their best non-album tracks.) Pop was the album where the thesis shifted from the late 20th century dislocation and media over-saturation of Zoo TV to a more brazen, warped embrace of all the trashiness of pop culture and the commodity of a department store chain like Kmart. Pop was the album with “Discothèque” on it.

Many would have you believe Pop is the nadir of U2’s work, even against their clearly less-inspired 21st century albums. Initially, the album actually arrived to mostly strong reviews and sales, though the latter would taper off and stagnate relative to U2’s usual financial success, and the reputation of the album would tank within years. The established critical narrative for the band often counts it almost alongside those misjudged bids for continued cultural relevance by classic rock artists, U2’s version of the bungling perpetrated by ’60s greats in the ’80s. There was fan backlash to the garishness of it all, like Pop and PopMart finally took Ironic U2 too far. In both camps, it’s amazing how much the album gets reduced to “Discothèque” as a signifier of how the band had lost their way — the self-mockery of their Village People impression in the theoretically disposable dance-rock song’s video the jump-the-shark moment of U2’s performative ’90s shallowness. Its reputation wasn’t rehabilitated by the band at all, either. Even in the immediate aftermath of the record, they talked of the frustrations during recording, the frustrations with having to (by their estimation) rush the album out. They’ve talked about wanting to go back and re-do some of those songs. Live, they hardly ever touch the album, if at all.

On some level, the criticisms are understandable: at sixty minutes, Pop is a lot to take in. A crowded album full of different themes and sounds melting together. Even if you aren’t one of the people who could never get with U2’s about-face in the ’90s, there’s no denying the songwriting on Achtung Baby is more bulletproof than it is here; one thing the band is right about is that some of the tracks on Pop could’ve used a bit more refining. As it’s often been noted, Bono’s voice — long a signature quality of U2’s music, especially the rich boom it had matured into for The Joshua Tree and the moody croon he found for Achtung Baby and Zooropa — showed its first glimmers of weakening and cracking. Having pushed it too far on massive tours, he sounds frayed around the edges, reedier. If you look at Pop as a haphazard album, the work of musicians straining against themselves and circumstance, it isn’t hard to hear Bono’s graininess as giving voice to the whole struggling enterprise of the album.

Pushing further into the electronic influences that had already characterized their ’90s work, Pop did indeed find U2 trying to incorporate club music into their sound — not that outlandish considering dance music’s legacy in Europe and electronica’s brief pop moment in America during the late ’90s. Plenty of alternative-rock bands of various sounds and generations got curious, incorporating samples and loops into their music and eschewing big guitar riffs. U2 were seeking to change up their songwriting process, so they too dove headlong into loops, sequencing, and a whole array of effects and studio tricks. (Larry Mullen, Jr. was also unable to contribute drums earlier on in the recording due to a recent back surgery.) The paradox of Pop, however, is it doesn’t exactly go far enough. Some dismiss it for U2 dabbling in the wrong trends for their sound, but there’s just as much of an argument to be made that they didn’t lose themselves as much as they should have in order to make Pop as singular a left-turn as they might’ve wanted at one point. There might be the skittering pulsations of “Mofo,” but there’s also the fairly straightforward U2 pop of “If God Will Send His Angels” and “Staring At The Sun” right after.

All of that being said, here are the other things Pop is. Pop is the freakout and comedown at the end of their ’90s road, where they lost the battles of Zooropa and fully embraced rockstar trappings, the dirty glamor, the glitz and crassness. The album signaling U2’s last brush with unfettered and fearless experimentation. The album where the mingling of sex and religion from Acthung Baby continues, but is pushed into Pop Art overdrive while deepening the conversation: Sin and materialism and indulgence are entangled with shaken faith. The album where they bred European textures with boom-times Americana, getting at something more real and immediate and sinister and shiny than those late ’80s ventures where they supposedly got closest to American themes. Almost written out of their narrative but pivotal to it, Pop is the album that remains most perplexing and fascinating and layered in a career of thoroughly analyzed classics.

Pop indulged and exposed a side of U2 never really seen before or after it. It is a decadent album, not only because it’s a clearly expensive, labored-over album by a superstar band, but also because it’s a loopy, druggy thing overall. U2 sounded like many places and times over the years, but there’s never really a time where U2 sounded so much like designer drugs on speedboats or in clubs, hallucinogenics on the beach. (The corroded song “Miami,” after all, came out of a debaucherous interlude in its Floridian namesake during the lead-up to Pop.) This characteristic persists through much of the album: the seedy sheen of “Mofo” and “Last Night On Earth,” the sun-drenched guitar cries in the chorus of “Staring At The Sun,” the swooning Technicolor hymn of “The Playboy Mansion,” the bleary-eyed day-after meditations in “Please” and “Wake Up Dead Man.” Bono once characterized the album as beginning at a party and ending at a funeral, moving from its uptempo club tracks to the broken-down gravity of its conclusion. But throughout, Pop moves through day and night repeatedly, weaving the rise and the comedown, the sublime and the profane, into a hybrid where the polarities become indistinguishable.

This complicates the name and theoretical manifesto of the album. They titled it Pop because of a play on mass culture, on disposability, but it’s also the moment where they become that stuff entirely: They’re rockstars here, and they’ve had the attendant life experiences. But try as U2 might — and this might be part of why people still have issues with their ’90s material — they could never fully go in that direction. They always had their earnestness, and these songs have more weight and bigger ideas than the intentional schlock of “Discothèque” or PopMart’s lemon spaceship would suggest, or than they’ve been given credit for.

That might be a failing in the eyes of some, but it’s also the exact thing that makes ’90s U2 so fascinating, and so rewarding to delve into. For all the riches and complexities of their ’80s development, the younger U2 still always turned to wonder in the end. The ’90s is where they grew up, and wrote a decade of songs that fought much harder to find that wonder. Pop has as much crisis of faith yearning as its immediate predecessors, but its darker moments approach U2’s absolute darkest. Everything is in hyperdrive here, and it accentuates the vulnerability of the humans within it — whether we’re talking about just slightly off-kilter, otherworldly balladry of “If God Will Send His Angels” or the rabbithole of “Mofo.”

There’s no better summary of all this tension than in that latter example. Like Zooropa’s “Lemon” before it, “Mofo” employs the supposed superficiality of dance music as a vessel for Bono airing out one of his most persistent demons, the early death of his mother. Where “Lemon” used shimmery, plastic future-disco to talk about preserving memory via technology, “Mofo” is the amphetamine rush through blurring, fading snapshots of the past. Bono mutters, then wails “Mother” throughout, issuing desperate pleas into the growing maelstrom of twisted synths and rhythms around him. 20 years later, it sounds very much like a late ’90s song sonically. And that belies what’s going on here, and thus what’s going on all over Pop. “Mofo” is nothing short of exorcism, and many of the record’s other highlights similarly grapple with heavy themes within the bait-and-switch of glistening surfaces that cede rather easily to reveal the simmering, festering frameworks within them.

Like Zooropa, this is the power of Pop: the idea of human emotions and voices lost in the post-industrial noise enveloping them. The difference here is that those crisis of faith moments litter the album — maybe the band felt listless, and were writing listlessly, but that’s part of the album’s impact. At one point in history, U2 spent their time on the tour bus reading the Bible, which must have been the most fun tour ever. By Pop, those older guys who had lived a bit of life were singing about broken religion and beliefs all around: the struggle of relationships and human connection in “Do You Feel Loved” or the alternate-universe lounge music of “If You Wear That Velvet Dress,” the pop singer midlife-crisis of “Gone,” the search for answers that crop up differently in “If God Will Send His Angels,” “Staring At The Sun,” “Please,” and most particularly “Wake Up Dead Man.”

On “If God Will Send His Angels,” Bono sings “God’s got his phone off the hook, babe/ Would he even pick up if he could?” and “Jesus never let me down/ You know Jesus used to show me the score/ Then they put Jesus in show business/ Now it’s hard to get in the door.” By the time “Wake Up Dead Man” closes the album, Bono’s gotten some time on the books, or at least started calling the direct line. “Jesus/ Jesus help me/ I’m alone in this world/ And a fucked up world it is too/ Jesus/ Jesus tell me the story/ The one about eternity/ And the way it’s going to be” he sings before the first restrained reading of the chorus — “Wake up, dead man.” The tone is hard to pin down. Is it a legitimate prayer for salvation, a sardonic-leaning address to Jesus about the Second Coming? Is it a disenchanted transmission to a concept Bono doesn’t know if he believes in quite the same way anymore, the sound of a man trying to hold onto the defining structures in his life? The way Edge’s arid guitar parts in the chorus unravel then swarm again over Mullen’s drum fills feels like bonds tightening, then breaking apart, then tightening again. Is it the sound of Bono talking to himself as much as anything, calling out to a lost soul and demanding “Wake up, wake up?”

After the push-pull of Pop’s split identity between clearly adventurous songs and more standard U2 material given a digitized facelift, this is where it ends: a strung out paean that after small eruptions, clatters to an end. It’s one of the greats in a handful of U2’s strong closing numbers, and the logical conclusion of Pop whether you buy these songs’ latent concerns or not. After all the album’s excesses, it ends on a song that shambles through the early morning hours, possessed by resignation as much as the desire for new resolutions.

Maybe people were right to look back on Pop as an unfocused album by people who didn’t know where they were. But whether the band recognized or intended that in the moment, that’s why Pop remains one of their strangest and most engrossing works. It works in little vignettes: the mind-altering party music shield of its first three tracks, the yearning middle section, giving way to the bizarre celebrity and fashion addled lust triptych of “Miami,” “The Playboy Mansion,” and “If You Wear That Velvet Dress,” and finally the crash landing reckoning of “Please” and “Wake Up Dead Man.” They collect to tell the story of one of the most famous bands ever, still at the end of the height of their powers, trying to locate the meaning in something. It sounds like people who have lost themselves, lost what they were looking for, lost their anchors — and answered it with an attempt to go deeper, weirder. Sometimes they fumbled, but the freak-outs fold into the DNA of Pop as a great album, in all its haggard, Day-Glo, trainwreck glory.

In an interview from 1997, Bono characterized Pop as the “logical extension” of what began with The Joshua Tree. It’s hard to know what the band themselves would mean by that exactly. Were they referencing the forward momentum of experimentation they threw themselves into after their breakthrough and its middle-of-the-road epilogue? Were they referencing those aged, conflicted conversations that dominate Pop vs. The Joshua Tree offering the sound of four dudes in their mid-20s first throwing their arms around the world? No matter how you interpret that 10 year arc, they could never go back after releasing The Joshua Tree, and they could never go back after Pop — though in a very different way.

U2 has always had a complicated relationship with the word “pop.” At various times in their career, they’ve presented themselves as alternative in some capacity, whether as young post-punks from Dublin or avant-garde “artistes” hanging in Berlin just as the Wall collapsed. And even their most major works often feel slightly out of time. The Joshua Tree or All That You Can’t Leave Behind define their eras more so than they sound birthed from them; U2’s ’80s work is of the decade but doesn’t sound like the decade. In the mid-’90s, Bono balked at Zooropa — likely still their weirdest full-fledged album — garnering a Grammy from an Alternative category. This is a band who grew fascinated with celebrity and the largest scope possible within pop culture, who grew fixated on their continued relevance and hit-making potential, but also never abandoned their inherent stubbornness. For a long time, the mainstream came to them, so it worked.

A combative relationship with the term and idea of “pop” is what was at the core of Pop — a hit-making band now part of the younger pantheon of the classic rock lineage, embracing the grosser directions of pop culture. The songs themselves are way poppier and more hook-driven than several of their other albums, but they’re couched in what was then forward-thinking electronic music that would have definitely seemed avant-garde to your average casual U2 fan who went to the show to hear The Joshua Tree singles and “Pride” and “Sunday Bloody Sunday.” In an un-cynical way, it is a midlife-crisis album. Especially considering what it wound up doing to them: The greatest irony of the end of U2’s irony days is that the album named Pop, the one hung up on all things mainstream and what it all meant, registers as one of their most significant stumbles. It is something they’ve been reacting to ever since.

The line Bono favored when describing Pop’s followup All That You Can’t Leave Behind in 2000 was that U2 was “reapplying for the job” of the biggest band in the world. This is the kind of talk that, over the course of the last seventeen years, would contribute to a younger generation looking at Bono and the rest of the band with a general eyeroll. But it’s also telling, how much Pop left a scar on U2. From there, they’ve talked through every album cycle, or the yawning four or five year gaps between releases, about the drive, the need, to remain relevant. Pop wasn’t that quite yet. Those were still young-ish men incorporating cutting-edge sounds and techniques and broadening their identity. The U2 since has oscillated between being very conservative or dabbling in trends too late. They are older men, no less or more obsessed with contemporary relevance than they were in their 30s, but looking all the more ridiculous for it as the years pass.

After Pop, All That You Can’t Leave Behind found U2 folding the electronic influences into their music more subtly, stripping back the arrangements, and generally espousing a “back to basics” approach. A return to what they do well: big, swelling pop songs like “Beautiful Day” and “Walk On.” Nothing they had done before sounded like that album, but it gets characterized as some kind of “return to abstract form” anyway, the moment U2 righted their course and embraced their core strengths. If Pop was the first severe dent in the band’s stature, this was the way of shoring up the defenses for years to come, and U2 have yet to stop reacting to that either: the turn from the failings of Pop to the rejuvenation of All That You Can’t Leave Behind.

Since then, they’ve released just three albums. How To Dismantle An Atomic Bomb arrived in 2004 and basically repeated what All That You Can’t Leave Behind did, with more of a rock angle. It took five years for No Line On The Horizon to materialize after that, and when it did the band talked it up like it’d be a left-turn on the level of Achtung Baby. But it wasn’t; they couldn’t commit on that level anymore, they still had to overcrowd it with something for everyone and their misguided attempts at a big single. (In the context of that album, it was the woeful bid for another “Vertigo,” “Get On Your Boots.”) Then it took another five years (and who knows how many songs or projects, considering reports of U2 working with RedOne on a “club” album and maybe Rick Rubin on another rock album and Danger Mouse on something, etc., etc.) before Songs Of Innocence arrived. And that’s it, the end destination of what the Pop/All That You Can’t Leave Behind one-two begat: an album that felt focus grouped into existence, U2 too possessed by the questions of what U2 are supposed to be and sound like to simply write a great new U2 album. So they arrived at the classic rock moment where they appear as shadows of themselves.

In the ’90s, U2 had the willingness to fall on their faces, even if that willingness was calculated. Today, they seem oblivious — it takes a lack of awareness to think that, hey, dropping Songs Of Innocence onto everyone’s iPhones might not result in a resounding chorus of hallelujahs. But they are also cripplingly self-aware, always heavily criticizing themselves a few breaths away from self-aggrandizing. This is part of Pop’s lasting damage, that it retroactively diminishes the standing of ’90s U2 as a whole — if this is what it was all leading to, surely the thinking that preceded it was also folly, right?

“The right to be ridiculous is something I hold dear,” Bono sings on “I’ll Go Crazy If I Don’t Go Crazy Tonight,” one of the hit single attempts that marred No Line On The Horizon. By 2009, that was a cringe-inducing line from him: The version of the band we had now was the hammy, classic rock kind of ridiculous. A safe ridiculous. But throughout the years, U2 did have a sense of the absurdity of what they were doing: As much as they were true believers in the transcendent properties of pop music, they also poked fun at themselves for the patent ridiculousness of getting up onstage and being a rock band.

This is the version of U2 that’s missed after Pop. The guys who admitted this whole thing was a bit of a farce, but actually acted on it, too — the guys who were willing to take some chances. The “ridiculous” line is laughable because all U2 wants to be now is “U2,” and they make creative decisions — now always long-gestating and overcooked in an attempt to marry the idea of the band with their idea of what could make the band as vital as they were twenty and thirty years ago. None of that is coming back. For those of us still (somehow) this invested in this band, it’s easy to keep wishing that U2 has one more great adventure in them — that they’d really go for it. They hedge their bets now. The turning point of Pop was that U2 made an album that would end their time as a band that innovated, and reimagined themselves, surprising us over and over. Ever since, they’ve been U2 as we expected them.