 In 1993 , U2 were in Europe for the " <unk> " leg of their Zoo TV Tour . Before their 3 July show in <unk> , Italy , the band received a <unk> from Radio <unk> <unk> I <unk> asking for an interview regarding the situation in Bosnia . The band agreed and met with an American aid worker named Bill Carter , who acted as the station 's foreign associate , due to Serbian travel restrictions . Carter described his experiences in Sarajevo helping Bosnians while surviving the dangerous living conditions . Lead vocalist Bono was <unk> to hear that those living in makeshift bomb shelters in the city played music , including U2 's , at loud volumes to drown out the sound of explosions . While in Sarajevo , Carter had seen a television interview on MTV in which Bono mentioned the theme of the <unk> tour leg was a unified Europe . Feeling that such an aim was empty if ignoring the Bosnians ' plight , Carter sought Bono 's help . He requested that U2 go to Sarajevo to bring attention to the war and break the " media fatigue " that had occurred from covering the conflict . 
