The screams are deafening. By the volume alone, you'd think a major Marvel star just appeared in front of the thousands of fans gathered in the Dolby Theatre. And to be fair, one did: Chris Pratt has just taken his seat onstage. But the fans are here for something a little more small town – literally – than a Guardians of the Galaxy or Avengers premiere. It's the 10-year anniversary of the Parks and Recreation series premiere, and Pratt along with series stars Amy Poehler, Nick Offerman, Rashida Jones, Adam Scott, Rob Lowe, Retta, Aubrey Plaza, Jim O'Heir, Aziz Ansari and creator Mike Schur have reunited to wax nostalgic about the cult-favorite comedy that only went off the air four years ago.

But it's clear from the sold-out PaleyFest 2019 crowd that four years has been too long to see all the Pawnee government officials in one place. Some of the biggest screams of the night came during a surprise appearance by Pawnee's own news anchor Perd Hapley (Jay Jackson), who introduced the panel's moderator Patton Oswalt – a self-proclaimed Parks and Rec superfan – in his trademark style: "Good evening, I’m coming to you tonight from where I’m standing, which is here. The story of tonight’s event is that it is happening."

While the heartfelt and hilarious panel kicked off with Poehler tearing up through her big smile at the passion of the crowd, it quickly became the stuff of any Parks and Rec superfan's dreams as Schur and the cast revealed so many fascinating and never-before-heard facts about the making of the series. 10 years later, this show still continues to surprise us.

Couldn't make it to the reunion yourself? Collider's got you covered. Here are the 11 highlights from the Parks and Rec 10th anniversary PaleyFest panel about all the things you didn't know about the making of one of the best comedies of all time (yeah, we said it).

How 'Parks and Rec' Came to Be

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It's not hard to see the similarities between Parks and Rec and The Office, which Schur worked on along with Greg Daniels, who adapted the popular British comedy for American TV. And that's because while the two shows don't share the same "extended universe," Parks and Rec is an unofficial spinoff from The Office.

"When I set out to create the show the idea was, [Greg Daniels] had adapted The Office and The Office was a fictional business. There's private sectors and we decided to do the fictional public sector," Schur says. "And then immediately it became like, 'Oh if this lasts for a while it can be a whole world.' If we're going to invent a fake town we'll have a fake government and we'll have fake people who come to these meetings, and we'll have newscasters like Perd Hapley types."

Ron Swanson Was Based on a Woman

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In doing research for who the characters of Parks and Rec would be, Schur and Daniels met with a real government official based in Burbank. That's who would eventually become the inspiration for Offerman's Ron Swanson.

"They found a city official who is a Libertarian who hates the government," Offerman says. "And she's a woman, interestingly, and that's the end of where Ron Swanson began."

Chris Traeger Is LITERALLY Rob Lowe

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Lowe joined Parks and Rec back at the end of Season 2 along with Scott as their characters Chris Traeger and Ben Wyatt were sent to Pawnee to help solve the city's crippling debt issues. But while they began as antagonists for Leslie Knope, soon the two men would find a new life and love in Pawnee and quickly become part of the beloved Parks and Rec family.

And it turns out that Chris is actually pretty much just Lowe in real life. During Schur's first meeting with Lowe back when they were discussing him joining the show, Schur had to ask the actor about how he had bought the entertainment company Miramax (which is a true story).

“Rob says, ‘I’ll tell you the story, I was literally on a yacht … ’" Schur says. "Before that sentence, Chris Traeger didn’t exist. Then he said, ‘I was literally on a yacht’ and my mind went blank and then after that, that was who Chris Traeger was.”

Schur later gave Lowe the writer’s notes from after their first meeting and it solved a years-long mystery for Lowe. “I always wondered how much of Chris was me and how much of Chris was Mike,” Lowe says. “And in your notes, it literally – there I go! – it says, ‘He says 'literally' all the time!'”

That catchphrase took on a life of its own thanks to the show, as Lowe recalls that "someone told me that they had to change the definition?"

"Yeah, this is true," Schur confirms. "Webster's Dictionary changed the definition of the word literally to mean either literally or figuratively."

Adam Scott Panicked Before Filming His First Scene

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It's hard to imagine now because Scott is so enmeshed into the DNA of Parks and Rec, but on the day that he filmed his first scene back at the end of Season 2, he freaked out.

"I remember very clearly waiting outside the doors to the hallway of the Parks Department, Rob and I waiting outside the doors to be cued to come in and start playing our [characters for the first time]," Scott says. "And then I remember waiting out there for the P.A. to point to us to walk in and it seemed like, 'Holy sh-t. Okay, Rob Lowe is standing next to me. And I'm now on this show that I like, I watched the show so now I'm inside the show.' I can't stop thinking about Rob Lowe and being inside the show."

Schur then quips, "Had you never acted before?" and the audience laughs.

Chris Pratt and Aubrey Plaza Are Basically Andy Dwyer and April Ludgate IRL

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The most unlikely of couples quickly became one of the best parts of Parks and Rec when Andy Dwyer and April Ludgate fell in love. And according to Pratt, that happened kind of on accident.

"I do remember that there was an episode where everyone was hunting and I didn't get to go," he says as the audience laughs. "We had to stay back and it was really the B story that they were cutting back to as everyone was off at this hunting lodge and I think someone gets shot. So we were just manning the Parks Department. It was like a chemistry reading during the making of the show. We just really got along and it was like this cat and a dog and we fell in love."

"It was my idea," Plaza deadpans.

Watching their back-and-forth onstage, it's hard to see where the actors stop and the characters begin. Pratt's golden retriever-like energy and wide-eyed enthusiasm as he speaks is so perfectly juxtaposed with Plaza's straight, intense stare and monotone. They really are their characters!

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When the moderator points out how wild it is to see Parks and Rec ideas like Galentine's Day and Treat Yo' Self become part of the real-world vernacular, Schur actually gets a little sad.

"Just this year it kind of bummed me out because like I’d go on Twitter and it would be like, ‘Hey ladies, this Galentine’s Day why not share a Mountain Dew Code Red?'" he says. "What does that have to do with Galentine’s Day? It was like appropriated by every brand and it kind of bummed me out.”

And Retta, wearing an amazing customized dress embroidered with Donna Meagle's catchphrase "Treat Yo' Self," feels the same way.

“Try walking into Target and all you see is Treat Yo’ Self," she says. “It’s obnoxious. I was like what the f-ck?

Some of the Most Iconic Lines Were Improvised

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Image via NBC

There's no denying the sheer brilliance of Schur and Daniels when it comes to the show's writing, but it turns out that some of the most iconic and GIF-ed lines from Parks and Rec were actually improvised during "fun runs." Those were the takes that happened last for every scene where the actors could just go wild and try out something new.

"That was always the goal: to reserve five minutes for the actors to just do whatever they wanted and sometimes things happen that we would go, 'Oh wait, let's use that!'" Schur says. "And we would do another full take of the scene with a new line or a new joke."

Usually the fun runs were X-rated and ended up on the blooper reels but sometimes they would actually strike gold.

"'Stop pooping' is fun run," Lowe reveals. And Schur credits Pratt with coming up with Andy's "Leslie, I typed your symptoms into the thing up here and it says you could have network connectivity problems" during a fun run as well.

The Heart of ‘Parks and Rec’ Was Always Leslie and Ann

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The comedy was hilarious, the romances were epic but Parks and Rec wouldn't be the show it was without the BFF duo of Leslie Knope and Ann Perkins. No matter how big the series became or the new characters and stories introduced, Schur reveals that Parks and Rec would always be about that friendship first and everything else second.

"This show is a show about female friendships, about Leslie and Ann's, that was the core of the show," he says as the crowd cheers and Poehler and Jones hold hands onstage. "That's why the pilot got us that meeting. And the saddest I ever got on the set was the episode where Chris and Ann were leaving because it was the end of an era and also because Rashida and Amy were very good friends in real life."

Jones praises how Parks and Rec portrayed a realistic female friendship, and how it's rare to see two women on TV who don't agree on pretty much anything still be so close and supportive of each other despite their differences and not be catty or in competition. She also reveals, to more cheers, how she and Poehler's real-life friendship is pretty much a mirror of Ann and Leslie's. That's why the episode "The Fight" was such a success – it was almost all improvised by the two women.

Since Poehler also wrote and directed the episode, the other cast members decided to hold a contest, SNL style, where they would try to make her laugh behind the monitors during their drunk "talking head" scenes. Again, it was all improvised, and that's where Ron Swanson dancing in a tiny hat came from. You can thank Offerman for that!

Adam Scott Was Inspired by Ben Wyatt’s Obsessions

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One of Ben Wyatt's best traits is his love for anything nerdy. Batman? He bought a full Batsuit (and wears it!). Board games? He made his own wildly successful one. Game of Thrones? He sits on the actual (replica) Iron Throne.

But when Scott first began playing Ben, he had never even seen Game of Thrones. Now, he loves it and it's all thanks to Ben's obsession. “After mentioning it a couple of times on the show, I started watching it and I could not be more into Game of Thrones,” Scott says. But as for Li'l Sebastian? "I still don’t get it.” he deadpans.

The FBI Is Monitoring Chris Pratt (in a Good Way)

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While the FBI is probably (definitely) monitoring everyone, it turns out they're huge fans of Andy Dwyer's love for the FBI with his Burt Macklin alter ego.

"My relationship with the FBI in real life is legit,” Pratt says. “Especially now, I think they’re just really happy to have someone in the zeitgeist that’s like, ‘I love the FBI.’" And according to Pratt, they'll now leave him FBI care packages filled with merch in his hotel rooms. How they got his location and room number is anyone's guess.

The Perfect Way to Say Goodbye, According to Ron Swanson

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When the Parks and Rec sets were getting bulldozed after the show wrapped its final season, Schur couldn't bring himself to watch. But Offerman secretly went to set and took all the doors from the sets, repurposed the wood and made them into canoe paddles with the Pawnee seal on each one as goodbye presents for Schur and his fellow cast members.

“It was perfectly good red oak,” Offerman deadpans. Now that's the most Ron Swanson way to send off the show.