Songfacts®:

• Linkin Park's Chester Bennington told MTV News that this mid-tempo ballad is one of his favorite tracks on A Thousand Suns. He said: "I think that 'Waiting for the End' and 'Iridescent' are probably tied at #1 [for my] favorite song on the record. I just think they're really beautiful. They're different. I like the way 'Iridescent' builds and climaxes."
• A remixed version of this contemplative ballad featured on the soundtrack of the Michael Bay-directed movie Transformers: Dark Of The Moon and played over the film's end credits. Speaking to MTV News, Mike Shinoda of Linkin Park said, "We put out the record in the late part of last year and even though it's never been a single up until this point, [when we played it live] you could really hear the singing pick up momentum during that song. It was just something that seemed a natural fit."
  
  He added that the hopeful tone of the song appealed to both the band and to Bay. "We loved that part of it when we were in the studio, but Michael actually loved pairing it with the movie because there's something that he feels it speaks to about the story line."
• This was the third Linkin Park contribution to the Transformers franchise. Their songs "What I've Done" and "New Divide" were featured in the first two films. Said Shinoda: "The Transformers collaboration has been really fun for us. I mean, we grew up playing with the toys. When we first got approached on the first one, we said yes based on the idea of taking that thing that we loved so much and bringing it to life in a modern way. As it's gone on, that's still a big part of it for us."
• You think the Joe Hahn-directed video is kinda confusing? It turns out his Linkin Park bandmates think so too. "All I know about the concept is that Joe Hahn sent me an e-mail that said something about 'In the valley of the blind, the one-eyed man is king,' or something like that," singer/rapper Mike Shinoda laughed to MTV News. "And the next thing I know, I've got horns growing out of my shoulders, and I've got one blind eye, and I've got a white dog and a snake on a throne made of antlers. I think you'd have to ask Joe what that all means."
  
  "As we've gone on, the videos have gotten more abstract," Shinoda added. "[And] I kind of like that, I've been encouraging it with Joe, because ... the stuff that goes on in his head is really interesting and really fun, and I think it probably comes from the fact he grew up reading a lot of comics, watching anime, those things. Especially in a video like this, you can tell the influences are there."
• Here's Joe Hahn's explanation of the video's concept in an interview with Noisecreep: "The video explores how human existence might be affected by the elements of Transformers robots and the threat of the Decepticons. What would it be like to be citizens in a decaying universe? I tried a lot of new things here, and we had a lot of fun shooting it."
• This was also used in the 2011 movie Kung Fu Panda 2.
• This is the fourth and final single from A Thousand Suns and relates to the album's theme of nuclear warfare with the singer dealing with the fallout. Revisiting the album on his Twitch stream in 2020, Shinoda explained how its apocalyptic theme reflected the climate of 2010. "Right now if you think of the state of America, it's so fractured culturally. At the time of A Thousand Suns, we were coming out the George W. Bush presidency and troops were still in Iraq. The idea that, 'Oh, we're just going to all blow each other up' was at the very top of the mind. So that influenced the lyrics a lot, that's why we used [in "The Catalyst"] the Oppenheimer quote and the Savio quotes about the machine, the pieces of the machine, all of that stuff was ambitious... some people thought it was too ambitious, or thought we were in over our heads. That's fine, but we were making what we were really feeling at the time. So that's the reason for the concept album kind of thing."