''When we were making our third record, the War LP, we were being thrown out of the studio by the studio manager because we had overrun or something and we had one more song to do. We wrote this song in about ten minutes, we recorded it in about ten minutes, we mixed it in about ten minutes and we played it, then, for another ten minutes and that's nothing to do with why it's called '40'.''
did you know
The lyric "3:33 when the numbers fell off the clock face" from Unknown Caller is a reference to the Bible verse Jeremiah 33:3. Bono refers to it as "God's phone number".