"I’ll never forget that day," says C.J. Pierce, guitarist for Dallas metal band Drowning Pool, of the day no one can forget. "I was laying in my bunk on the bus — a little hungover from the night before, of course, this is rock ’n’ roll, I had a couple drinks, whatever — and Clint Lowery from Sevendust comes running on my bus: ‘They’re bombing our country!’ I just remember him yelling, ‘They’re bombing our country!’"

Their bands were scheduled to play a show in Wisconsin. "It was an arena. It was a big show. And a lot of people showed up. The fans showed up, so we’re gonna play. I remember, we did a moment of silence. Each band. We still played the show."

It seemed obvious. Maybe it was. "What else can you do?"

The idea, after the terrorist attacks of September 11, 2001, was to do exactly what you’d done before, and listen to whatever you liked to listen to while you did it. Or the terrorists win.

For example. Jennifer Lopez’s "I’m Real," featuring Ja Rule, was the no. 1 song in America. Maxwell’s Now was the no. 1 album. Jay Z’s The Blueprint, Bob Dylan’s Love and Theft, and Slayer’s God Hates Us All came out that very day. If you’re inclined to view history through the prism of the music that inadvertently soundtracked it, 9/11 is unbeatable for tragedy, absurdity, and pitch-black comedy. But 15 years later, it’s the songs the radio wouldn’t play that tell you the most.

In the week after the attacks, Clear Channel Communications, the Texas-based radio empire then controlling nearly 1,200 radio stations reaching 110 million listeners nationwide, drew up an informal blacklist of sorts — more than 150 songs its DJs should avoid, so as not to upset or offend anyone. As a Snopes investigation subsequently revealed, adherence was voluntary, and many stations ignored it; at the time, sheepish anonymous employees described it to The New York Times as a corporate memo gone wrong, snowballing thanks to an "overzealous regional executive" who kept adding more songs and soliciting more input. A wayward reply-all email debacle made sentient.

And then the list leaked, and became an invaluable source of mild outrage and desperately needed comic relief.

"Imagine." "Ruby Tuesday." "Rocket Man." Rage Against the Machine’s entire catalog. Seven AC/DC songs, from "TNT" to "Dirty Deeds Done Dirt Cheap." "American Pie." "Free Fallin’." "Rock the Casbah." "Dancing in the Streets." "It’s the End of the World as We Know It (And I Feel Fine)." The list is uncomfortably corporate and painfully human, as notable for what it omits (there’s very little country, and no rap) as what it includes. It’s usually presented in alphabetical order, but you can plot the stages, follow the bonkers logic.

Phase one: Contemporary hits from various rock and metal bands, some with violent imagery, some just with the wrong vibe. Metallica. Godsmack. Soundgarden. Third Eye Blind’s "Jumper." Tool’s "Intolerance."

Next, pop hits of any era with vaguely confrontational, or war-adjacent, or morbid imagery. Pat Benatar’s "Hit Me With Your Best Shot" and "Love Is a Battlefield." The Gap Band’s "You Dropped a Bomb on Me." "Great Balls of Fire." "Dust in the Wind." "Knockin’ on Heaven’s Door," both the Bob Dylan and Guns N’ Roses versions.

Then, songs about aviation: Lenny Kravitz’s "Fly Away." Red Hot Chili Peppers’ "Aeroplane." Foo Fighters’ "Learn to Fly." Steve Miller Band’s "Jet Airliner." Peter, Paul and Mary’s "Leaving on a Jet Plane."

Finally, and most hilariously, the irony tier: songs so peaceful and utopian they might scan now as oblique taunts. "What a Wonderful World." "Bridge Over Troubled Water." "Ob-La-Di, Ob-La-Da." And just to be safe, Alanis Morissette’s "Ironic."

At the time, this story was an uneasy delight — in the teeth of the alleged Death of Irony, with Saturday Night Live and The Onion and all the late-night talk shows respectfully silent, you took your laughs where you could get them, and not much back then was funnier than "things are so bad out there they banned ‘Imagine.’"

But for the active artists who made the list, however unofficial and well-meaning it might’ve been, it had a profound effect. (The company, since rebranded iHeartMedia and still the medium’s dominant power, declined comment.) It bumped singles, stalled albums, derailed promising careers. And to listeners, to the American people, it was a whimsical interlude to the grim dystopia of George W. Bush’s war years, clearly signaling that the major corporations dominating the music industry were susceptible to panicked censorship and misguided patriotism.

It was a clumsy, confusing message to a shocked and thoroughly shook populace just when it needed music the most. Any music. Whatever you’re into. Whatever works. And it’s hard to interpret the act of banning every Rage Against the Machine song as anything but a quick and dirty attempt to manufacture a chilling effect on protest songs overall; indeed, with dismayingly few exceptions, prominent protest songs were sorely lacking as the wars in Afghanistan and Iraq unfolded. Songs that did directly address the national mood tended toward the pandering, the jingoistic, the geopolitically disingenuous: Think Toby Keith’s alarmingly brazen "Courtesy of the Red, White, and Blue (The Angry American)," or Darryl Worley’s syrupy strawman broadside "Have You Forgotten?"

Music was hardly the biggest focal point or the hardest-hit entity after 9/11, but the ripple effect was profound and dismaying all the same. The Clear Channel list was mostly comic relief, but the mood had changed dramatically two years later, when the Dixie Chicks dissed George W. Bush onstage in London, and triggered an instant, near-total blacklist so thorough and visceral they made a movie about it. This list was the first indication that both fallible, well-meaning humans and at least slightly less benevolent megacorporations had enormous influence over who and what you heard and saw. And as the national mood got darker and heavier, that influence grew more sinister in turn.

Here, in their own words, are recollections from five of the artists whose songs made Clear Channel’s 9/11 memo. The panel:

Corey Taylor, vocalist, Slipknot. The masked Midwestern metal band’s second album, Iowa, had come out in late August and was primed for a huge breakthrough; the list included their new single, "Left Behind," and their first big hit, "Wait and Bleed."

Serj Tankian, vocalist, System of a Down. Based in California, the flamboyant Armenian American hard rock band was in the same position with Toxicity, which had come out the week before. Unfortunately, the chorus of first single "Chop Suey!" was "Trust in my self-righteous suicide."

C.J. Pierce, guitarist, Drowning Pool. The timing of "Bodies," an instant nu metal smash from this young Dallas band, was even worse: Its extremely memorable and visceral chorus was just "Let the bodies hit the floor" ad nauseum.

Richard Patrick, frontman, Filter. "Hey Man, Nice Shot" was a massive 1995 alt-rock hit for this industrial-pop Nine Inch Nails offshoot; Patrick was famously inspired by the public suicide of Pennsylvania politician R. Budd Dwyer.

Barry McGuire. His spectacularly gloomy 1965 folk song "Eve of Destruction," written by P.F. Sloan, became a surprise hit so fast that McGuire, a young Oklahoma-born singer-songwriter out in California who’d recently quit the New Christy Minstrels, didn’t have time to cut a smoother vocal. He still performs it live today; the first line is, "The Eastern world / It is explodin’."

The Ban

Corey Taylor, Slipknot: Oh yeah. I remember all of it. The irony. Take out the event of 9/11, because it was so heavy for everyone. It was such a surreal moment in time. Now imagine trying to get back on with life, like everybody else was — that was the big go-to line. "You know what? Go back on with your life. We can handle this. Do not be afraid." You’re trying to play music. You’re trying to promote your album, and all of a sudden your songs are banned from the radio. You’re like, "What?"

C.J. Pierce, Drowning Pool: It was a long time before "Bodies" came back around. For us, we had just put out our record. It was our first single. We had just broken into the music business. Our manager called us up shortly after it happened, and told us that our song was off. I think we actually made some kind of record, the shortest duration of a single on the radio, because we’d just put it out, and they took it off. That definitely was a big blow in our career at the time. But there were more important things going on.

Serj Tankian, System of a Down: "Lucy in the Sky With Diamonds" was on the list. Anything with the word "sky" was listed as well. That was really interesting. Very strange time. We had the no. 1 record in the country, at a time when our single basically got kicked off the radio.

Barry McGuire: I was told that "Eve of Destruction" was a no-play. "Eve" has always been a dicey song for the general population. I remember, Geraldo [Rivera] wanted me to come back and do a show, talking about why they weren’t playing the song. But what difference would it make? You reach a point after a while, it’s like shoveling sand against the tide. Nobody wants to see themselves for who we really are. And that’s all "Eve of Destruction" was. A societal mirror.

Serj Tankian: "Imagine"? Oh, you’re kidding me. Think about that. All peace. All love. Yeah. Weird. Well, it’s a good lesson: When you have too much corporate control over one entity, one distribution channel, be it radio or anything else, it can get dangerous.

Richard Patrick, Filter: Originally, I was outraged. I remember thinking, "I kind of understand that people are sensitive, but, y’know, you’re messing with people’s livelihoods as well." I don’t think Drowning Pool ever really recovered from that. They were talking about a mosh pit, you know?

C.J. Pierce: It had nothing to do with anything but jumping in the pit and having a good time at a rock show. That’s what the song’s about. That’s what it means to us.

Corey Taylor: This is back when radio really meant something — it was still a viable way, honestly, to make a living. And to get your music out there. And when that went away, for lack of a better term, it felt like such a dick-tease.

C.J. Pierce: Yeah, it hit my career. To be honest with you, I don’t think we ever really recovered from that. But again. More important things going on than our stupid song.

The Aftermath

Serj Tankian: We went on tour the week after 9/11. It was very strange. You’d have huge gatherings of people at every show, and on the television you had all the orange danger lights and red danger lights, all the different degrees of danger that the country was experiencing. It was pretty scary. Our stage show got much quicker — we tended to move around way more than we generally did, to avoid any projectile possibilities.

Corey Taylor: It was a tense time for the audience. It was a tense time for us. I’m glad that we were there for each other. It was good that we had each other to lean on. And I think those first few months, it definitely allowed us to feel like, "God dammit, the fans are still here. We’re still here. We’re still free. We still live. Take a deep breath and fuckin’ cherish it." And then, encourage your fans to do that.

C.J. Pierce: Some people go work out at the gym, and they like to listen to metal, just to get pumped up. That’s all it is, man. To me, I’m the happiest, most positive person in the world, and I play metal. I just hate the fact that it gets censored, thinking that it’s gonna breed violence or something like that. It’s rock ’n’ roll. It’s metal. It’s just a heavier style of music. I don’t know why metal always gets targeted. But it has been.

Richard Patrick: I can understand their initial freakout, for maybe a week or so. Two weeks. But we, in general, we’re a pretty safe country. So when that happened, I think they kinda freaked out, and made a list.

Serj Tankian: "Chop Suey!" did really well, because it spoke to the times. Obviously we had no idea, writing the song and putting it out, what would happen after. But people seemed to kind of think of 9/11 with that song, and how they related to it.

C.J. Pierce: We started doing USO tours. We went over and played on active bases. We went to Iraq and Kuwait a few times. And the troops, they said they would listen to "Bodies" to get in the right frame of mind to do their job, to come home safe. We felt more of a sense of a reverse effect: Radio wasn’t playing it, but everybody else affected by the situation was listening to the song.

Serj Tankian: On 9/12, I had written a statement called "Understanding Oil" and posted it to the band’s website [the next day]. It was basically a very — it was a geopolitical thought process, trying to understand what had happened and how it was linked to our foreign policy of the past 50 years, et cetera. And it was really — we got a lot of heat for it. Death threats, you name it. It taught me a valuable lesson: It’s quite easy to speak the truth when public opinion is on your side. It’s not, when it’s not. It’s pretty painful when it’s not. But the truth doesn’t change.

Richard Patrick: At some point, I don’t know what happened, but everyone just wanted to be entertained by the pretty people. It was like the end of — it was like a place where all of a sudden the world became too horrified by reality, and then all of a sudden everyone wanted all their entertainment to be pretty. Even in movies and stuff like that.

The Lesson

C.J. Pierce: I always think it’s stupid, and ignorant, when they try to relate music to an insane person. Crazy is crazy, no matter what movie they watched or what song they listened to. That has zero effect. It has nothing to do with, "Oh, I heard this one three-minute-and-30-second-long song, and now I’m gonna …" It’s so ignorant.

Richard Patrick: Did it really impact me? Yes. Morally. They self-censored "Hey Man, Nice Shot" off the radio when everybody was saying, "Go back to your normal lives." And they took away our First Amendment rights. That’s not the way you respond to terrorism. You make the music louder. You make the movies bloodier. You make the video games whatever. All of that is an attack on freedom. That is an attack on freedom. Not playing music is an attack on freedom.

Barry McGuire: I was never gloomy. I thought we could wake up. If you go to a doctor, and he says, "Well, you have cancer here, but I think we can save it." Do you call him a protest doctor? He’s telling you that you’re sick. That you have a terminal disease, but it’s curable. And I thought that our disease was curable at the time. But we had to first wake up and admit that we had a disease. But nobody wanted to wake up. Nobody wanted to admit it.

Richard Patrick: My song is still kickin’ ass, and I’m very proud I wrote it. And I’m very proud that it’s about something tragic. I’m proud of that. Because we had a country that could hear it, and go, "Yeah, that is wild. Thanks for bringin’ it up. Thanks for mentioning that. That is something we should think about and understand." Because ever since then, it’s been Katy Perry and fireworks and happiness. Katy Perry’s doing a wonderful job. But she’s gotta do that, and I’ve gotta do this.

C.J. Pierce: We’ve had a handful of situations that have knocked us down. Obviously, our singer, Dave Williams, passed away from cardiomyopathy shortly thereafter, the summer following. That was another big blow. Kicked in the nuts. But I love music. Gotta keep on keeping on. As Dimebag Darrell would say.

Serj Tankian: I guess it takes you back to the Tipper Gore days. All the suits brought against Ozzy for people killing themselves, or driving themselves crazy. Turning the Beatles record backwards and coming up with weird things. People are always looking for stuff. I think harder music is always more scrutinized because it’s edgy. It helps provoke. That’s part of its use. That’s part of its agenda. Not always consciously. But rock is the preferred choice of rebellion. So when you wanna stop rebellion, then you’re gonna try to stop rock, I guess.

Corey Taylor: I’ve talked to a lot of people from so many different walks of life. Iowa really helped them not only wrap their heads about what was going on with 9/11, but also buried the burden of being young and fuckin’ gnarly. That, to me, that’s what we’re supposed to do. We’re supposed to be the soundtrack for the underdog. For the guy, or the girl, who is fighting through it, trying to make sense of this fuckin’ weird existence.

Barry McGuire: So as far as the world is concerned, I have absolutely no hope in my mind for the systems of the world. But, for the individuals in the world, I am completely optimistic. People can wake up and realize what’s going on. It’s really simple once you understand what’s happening. What to do.