"Everyone gets a little nutty after the end of a tour. You have physiological reactions that continue for months afterwards. Around about 9 o'clock you suddenly start going, 'Where's the show? Where's the show?'"
- Paul McGuiness on the ZooTV tour
U2 had planned to release the material for No Line On The Horizon as two extended plays, titled Daylight and Darkness, but during sessions in London in 2008 decided to compile the best songs onto one album.