If the Los Angeles band Xero didn't lose vocalist Mark Wakefield in the late '90s, they would've never met Chester Bennington — former frontman for the Phoenix rock group, Grey Daze.

The singer was introduced to Mike Shinoda, Brad Delson, Joe Hahn and Rob Bourdon through Zomba Music's Jeff Blue, and they had an undeniable chemistry from the start. They created a musical amalgamation of rock and rap out of their varying influences, and a whole new era of hard music was underway.

Linkin Park’s groundbreaking debut album Hybrid Theory came out Oct. 24, 2000. Often regarded as one of the best rock albums of the 21st century, it catapulted the band into stardom and kicked off a long, successful career for them.

Though the untimely death of Bennington in 2017 would ultimately put the band's future on hold, they're celebrating the 20th anniversary of their masterpiece with a reissue of the album, which features a bunch of demos and B-sides from the recording sessions.

In honor of the album’s anniversary, here are 10 facts you may not have known about Hybrid Theory.

1. Hybrid Theory was originally the name of the band.
Shinoda and Delson’s band Xero went through a couple of lineup changes prior to meeting Bennington. Once they settled on him as their new vocalist, they changed their name to Hybrid Theory, to describe the musical fusion they created. They eventually had to change their name again because of a Welsh electronic group called Hybrid. Thus, they settled on using the phrase for the album’s title.

2. It was originally a demo tape.
Linkin Park originally recorded a demo tape based on some songs Shinoda had written with Wakefield. While some of the tracks were renamed, the majority of the songs from the demo ended up on the album, with the exception of “Carousel” and “Part of Me,” according to the Linkin Park Association.

3. They played over 40 showcases to label representatives.
Once the demo tape was prepared, the band played over 40 different showcases to label representatives. “We just kept pushing,” Bennington reflected to Metal Hammer. “Most bands probably try out in front of three labels, get rejected and give up. We played in front of 45 but our attitude was, ‘These guys are fucking stupid if they can’t see what we’ve got.’ We knew what we had and never doubted it.”

READ MORE: Grey Daze Members Debate if 'Hybrid Theory' or 'Meteora' Is Better

4. The label tried to get rid of Mike Shinoda.
During the Hybrid Theory sessions, Warner Bros. actually tried to get rid of Shinoda. In fact, their label reps held a private meeting with Bennington to try and persuade him to kick his co-vocalist out. “They wanted some fucking rapper from New York who no one knew to come and do vocals on the record,” Bennington raged to Metal Hammer.

“I just wanted to punch those idiots in the face because they couldn’t see that golden fucking teat of awesomeness that was right in front of them. Mike’s one of the most productive songwriters of our era, I think. God knows how many Number Ones we’ve had, but if he wasn’t in the band, we wouldn’t have had any of those!”

5. Some of the album’s aggression came from conflicts while recording.
Producer Don Gilmore was more familiar with producing rock bands, so he gave Linkin Park a lot of creative freedom when it came to the hip-hop portions of the songs. But when the label wasn’t happy with what they were hearing, it started to cause some tension in the studio.

“The power struggle became part of what making that album was,” Shinoda explained to Billboard. “Some of the intensity and frustration you hear on the album is specifically album-related.”

6. “A Place For My Head” was one of the earliest songs Shinoda had written.
Shinoda told Metal Hammer that “A Place For My Head” was written right after he’d graduated high school. “The very earliest incarnations of the songs from Hybrid Theory were written at my parents’ house when I had just finished high school,” he recalled. “A Place For My Head” was one of those first songs, but I wasn’t thinking of writing an album — I was barely considering starting a band!”

7. Chester Bennington wasn’t initially a fan of “In the End.”
Though it would eventually become the biggest single on the record, and one of their biggest songs overall — Bennington wasn’t initially a fan of “In the End.” "I was never a fan of 'In The End' and I didn't even want it to be on the record, honestly,” he admitted to VMusic.

“How wrong could I have possibly been? I basically decided at that point I don't know what the f--- I'm talking about, so I leave that to other people who are actually talented at somehow picking songs that people are going to like the most.”

8. The “shut up” part of “One Step Closer” was inspired by Rage Against the Machine.
Shinoda revealed to Billboard that the part of “One Step Closer” where Bennington screams “Shut up when I’m talking to you” was inspired by Rage Against the Machine’s “Killing in the Name,” particularly the repeated “Fuck you / I won’t do what you tell me” line at the end.

“We wanted a part like that in one of our songs,” he said, pertaining to the Rage Against the Machine anthem. “And we were in the studio writing and re-writing ‘One Step Closer,’ and eventually we got so mad that Chester was just writing words down about how mad he was at Don for making us rewrite shit.”

9. “Crawling” and “With You” were the hardest songs for Bennington to sing.
In a chat with Linkin Park Underground, Bennington noted that “Crawling” and “With You” were the hardest songs for him to sing live. “I would say that ‘Crawling’ has caused me the most trouble live more than any other song,” he said. “Just because it’s that one long note the whole time, but I think probably ‘Crawling’ and probably ‘With You’ was hard when we used to play that one.”

10. It’s the best-selling debut album of the 21st century.
As of October of 2019, Hybrid Theory had sold over 32 million copies worldwide. It’s the best-selling debut album of the 21st century.

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