Last Night on Earth

Singer Billie Joe Armstrong explained to Q magazine May 2009 that "'Christian's Inferno' is like a subway ride to hell and you kind of end up in outer space with this" song. Bassist Mike Dirnt added: "It's the most unapologetic love song."

This song is a piano-led number. Armstrong learned the piano before recording 21st Century Breakdown and a lot of the songs were written on it. Bassist Mike Dimt told The Sun April 24, 2009: "There are parts of this record, which are the most melodic thing we've ever written." Armstrong added: "The piano was a new thing for us and I pushed my voice to do things it's never done before. I always hear a guitar symphony in my head all the time. How do you make song arrangements and push them further than they've ever gone before in the rock genre but still have it feel like you just heard a Ramones song? That's why Butch (Vig, producer) worked so well. He helped figure it all out. He's always been on our shortlist, since Nirvana's recording came out. But it was tough. You just have to keep ignoring the voices in your mind, telling you that you suck."

Armstrong told Billboard magazine that this "is a love song I wrote for my wife. I wrote it on piano and then sang it. It's one of those things where it's only directed toward one person, like an intimate moment. And you say, 'Wow, I never sang falsetto before, that's pretty cool.'"