Billboard is celebrating the 2010s with essays on the 100 songs that we feel most define the decade that was -- the songs that both shaped and reflected the music and culture of the period -- with help telling their stories from some of the artists, behind-the-scenes collaborators and industry insiders involved.

Putting a country artist and dance producer together for a pop radio hit would’ve been unthinkable decades ago. But the 2010s opened minds and ears to cross-genre collabs, and Zedd, Grey and Maren Morris’ 2018 team-up “The Middle” showed that no matter the genres of the artists behind it, all it takes is an undeniable hook and a powerhouse vocalist to help a song soar. 

Laced with unique sound effects from a ticking clock to a whipping axe, “The Middle” almost instantly became a ubiquitous hit, particularly thanks to its ridiculously catchy belt-along chorus. The song shot to the top of the Hot Dance/Electronic Songs chart in its second week and held strong for a then-record-breaking 33 weeks; it only took six weeks to break the top 10 on the Hot 100, where it eventually peaked at No. 5.

Though “The Middle” was an immediate success, it was a long road for Zedd, the Russian-German producer who had already scored a slew of hits thanks to other female vocalists like Selena Gomez and Ariana Grande; and Grey, the LA-bred sibling producer duo who teamed up with Zedd on Hailee Steinfeld’s 2016 banger “Starving.” The two and Morris worked in tandem with the song’s original writers, Sarah Aarons (who co-wrote Zedd’s 2017 smash “Stay”) and The Monsters & the Strangerz to perfect the track throughout 2017.

Aarons recalls “The Middle” sparking a big reaction with industry folks who heard the song in its demo stages that spring -- "Everyone was like, 'This song!'," she remembers -- and even before it was officially released, a plan was in place to launch its video at the Grammys in February 2018. 

The team tried out “The Middle” with 14 high-profile vocalists -- including Demi Lovato, Camila Cabello and Carly Rae Jepsen, as memorably detailed in a New York Times making-of video -- before Morris was recommended to Zedd in late 2017, just weeks before it needed to be ready for the Grammy video premiere. But everyone felt Morris was the one upon hearing her take. “I remember listening and being like, ‘Cool, we’re done!’” Aarons says.

While it never really crossed Aarons’ (or any of her “Middle” cohorts’) mind that Morris was a country star joining a dance artist on a pop record, the Australian songwriter remembers Morris receiving flack for the crossover. “It definitely is frowned upon in a way, but a lot of people were also really proud of her,” Aarons says, adding that Morris’ soulful voice works for both genres. “At the end of the day, she widened the scope of what’s possible for girls growing up in Nashville and wanting to be in country music -- or anyone, really.”

Morris was already a star in her own right at that point, as her debut album, Hero, reached No. 1 on the Top Country Albums chart in 2016, while the set’s lead single, “My Church” won the Texas native a Grammy in early 2017. “The Middle” arrived just days after Morris earned her first Country Airplay No. 1 with the lovelorn ballad “I Could Use a Love Song” -- a perfect-timing scenario that boosted Zedd’s newest release in a time when dance producers’ hits were more reliant on the star power of their vocalists than ever.

The song’s simple, vocal-driven chorus also fit in with the prevailing sound of Top 40, which Grey’s Kyle Trewartha calls “anti-loud” -- the opposite of the booming production of the EDM craze earlier in the decade. Kyle and his brother/bandmate, Michael, thought to add the chopping axe sound effect to “The Middle,” which helped the song prove that taking risks in pop music can work. “The fact that a song like this did so well kind of makes producers feel like they have some more room to make [a song] interesting,” Kyle says.

“The Middle” also struck listeners, though, because of its feel-good sound, despite the fact that lyrically, as Aarons puts it, “the whole song is turmoil.” Even so, Aarons argues that the upbeat vibe of “The Middle” was the ultimate coping mechanism for today’s tough political climate. “I always feel like I still need that one song that I get up in the morning and feel good,” she says. “I think [‘The Middle’] was that, but in a real way. When you can make straight-up pop music but put as much emotion in it as possible, it’s a win.” 

It also opened the doors for others to try out the country-dance combo. The Chainsmokers recruited Kelsea Ballerini for “This Feeling” in September 2018; Diplo kicked off a country project, Thomas Wesley, in April 2019, with a Cam collaboration. But none of those crossovers have proven to be as huge as “The Middle,” which also topped the Pop Songs, Radio Songs, Adult Top 40 and Adult Contemporary airplay charts and now has more than 787 million streams, according to Nielsen Music.

Aarons says she and her “Middle” creators still celebrate the song’s success every time the group gets together, and she recently heard “The Middle” during an Uber ride that reassured her of the song’s staying power. But no matter how often any of them hear it these days, Kyle can’t help wondering one thing: “I just want to know if people are sick of it yet.”