Bono announced that the new album by U2 would have a sound that was influenced by trance and metal.
The Irish band used Morocco as their inspiration to give their music on this album a special touch. They wanted to be able to give people the urge to dance.
Bono added that not only would this album would be different than their preceding albums, but also difficult to compare to any other artist.
U2 worked with Daniel Lanois and Brian Eno on this album.