‘Wow, this is a part of history happening. It’s bigger than just a song."

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.

The connection hip-hop has with its black music ancestry -- raw innovation; racialized pains and the desire to overcome them -- is often drawn with traceable lines. That link is the crux of To Pimp a Butterfly, the Kendrick Lamar sophomore major label album, which grew from a highly anticipated rap record to a cathartic monument by the time it dropped in March 2015. The opus’ brightest moment came from something as intangible and clichéd as perfect timing.

Kendrick Lamar and company sat for months on choir of Pharrell voices that became “Alright.” During that timespan, Akai Gurley and 12-year-old Tamir Rice were introduced to the nation not as sons, but corpses. “Alright” was finished a week before To Pimp a Butterfly’s release as its conspirators decided they needed that one beacon to shine through the album’s multi-genre thicket. In that quest for an undeniable LP centerpiece, they stumbled onto a generational hymn.

“We needed that high-intensity song but just didn’t have it yet. I just remembered that fact that we loved the skeletal version of the ‘Alright’ beat that Pharrell did,” Sounwave says. “In order for it to work, I had to make it feel like the rest of the album. I had to throw the live drums in there. People thought it was crazy to throw a saxophone on a song like that, so I had to tell everybody, ‘Trust me, it’s gonna feel right.’ I got Terrace Martin in there — he killed it.

“Once we finished that, it opened Kendrick’s mind to go where he went with it.”

Perhaps the closest 21st century analogue in terms of political and cultural impact is Jeezy and Nas’ “My President.” It’s materialistic, but the charm doesn’t rest in the blue Lambo; this is the ecstasy of having a black president, physical proof of there existing a limitlessness in being African-American. By the end of Barack Obama’s presidency, that dream corroded with reminders of black America’s mortality, crudely captured through cellphone footage.

And yet, “Alright” carries the temerity to hope. Kendrick valiantly raps through an impossible scope within three-and-a-half minutes, emphasizing arcane Christian and Greek mythology references, riling against homicidal police, brooding about temptation, and ending it with a coda that strives for self-love. Producer Pharrell magically condenses those complexities with a four-word refrain. His voice is bass-less but resolute, jubilant but not quite naive.

In plainspoken terms, “Alright” was a banger, earning Kendrick two Grammys and a modest No. 81 peak on the Hot 100. But the anthem’s significance lies in how black America’s cross-generational link to the struggle for the liberty they’ve been denied extends beyond teachings to pass on -- it’s felt. That’s how a song becomes centripetal to a new age civil rights movement, from Black Lives Matter marches, to Cleveland protesters bravely chanting after being pepper sprayed by police, to Chicagoan Trump protesters singing it after canceling a rally appearance, and onward.

And perhaps the next generation will have its “Alright” when the time comes to demonstrate once more, just like the ones prior had “Fight the Power” and “A Change Is Gonna Come.” It’s a heavy honor for the songwriters: Perhaps in a better world, there wouldn’t need to be such protest anthems.

“We were on the set of the Ellen show when [Kendrick] was performing,” Sounwave says, remembering the moment when he realized the song became a rallying cry. “One of our guys showed us a video of [people protesting to ‘Alright’] and what they were chanting. Goosebumps were happening: ‘Wow, this is a part of history happening. It’s bigger than just a song.’ It’s a bittersweet moment. Yeah, it’s a big thing your words touched this many people, but at the same time, it’s like, ‘Why do we still have to make these songs?’”