13. 'Wave of Sorrow (Birdland)'
This Joshua Tree outtake was so inspired by Patti Smith that they added "Birdland" — the title of a track from her 1975 masterpiece Horses — to the name of the song. Bono wrote the song when he travelled to Ethiopia after Live Aid and realized the money raised by the massive event would barely dent the overwhelming problem. The title comes from a Langston Hughes poem. They never quite felt the song was done, and in 2007 when they released a 20th anniversary edition of The Joshua Tree they fleshed it out.