Mac Miller was not only a great rapper, he was a great collaborator. He worked with some of the best artists and producers in the game throughout his dense discography, especially on his 2011 mixtape Best Day Ever. In honor of his legacy and Best Day Ever’s 10-year anniversary, some people who worked with Mac talked about how the iconic project came together.

While speaking to the Recording Academy, legendary beatmaker Just Blaze revealed he didn’t charge Mac Miller a dime to produce his song “All Around the World,” a standout on the mixtape.

“That record, and a few other records [at the time], I didn’t charge anything for,” he revealed. “I was really just trying to test the room. I was able to help a few artists with their careers or help them get their start. I was happy to be a part of that with him. Again, we never had a formal business arrangement. Sometimes it’s just an artist you believe in and you try to support them however you can.”

Blaze’s “All Around the World” beat samples MSTRKRFT’s “Heartbreaker” featuring John Legend that dropped back in 2009; the producer revealed he actually knew two band members who played on it and asked them for the stems directly.

“With ‘All Around The World,’ he had already cut a demo. I was just finishing my new studio. That song contained a sample of ‘Heartbreaker’ by MSTRKRFT. Jesse [Keeler] and Al-P of MSTRKRFT were old friends of mine,” he explained. “I was like, ‘I can get you the stems to this record and make it into something.’ They sent me files to the original version. We added the actual stems from the original sample and got it done. It wasn’t a big thing. To be honest, I had just finished my new mix room and I was trying to test out the room and figure out what we needed to fix or change.”

Reflecting on the 10-year anniversary of the project, Just Blaze said it’s crazy how fast time moves, especially when you’re caught up in a history-making moment.

“Time flies. When I thought about it, I was like, ‘Damn.’ It’s hard to believe it’s been 10 years. And it’s harder to believe it’s been as many years as it has been since he’s been gone. To be honest, a lot of times when you’re making history, you’re not thinking about the fact that you’re making history when you’re doing it. You’re too busy being in the middle of it.”

Other collaborators, including Wiz Khalifa, SAP, Krysis, and more also spoke on the legacy of Mac and Best Day Ever. Read all their accounts here.