 Recording sessions for The Joshua Tree began in January 1986 in <unk> House in Dublin , Ireland , and continued throughout the year . U2 briefly interrupted these sessions in June to join Amnesty International 's A <unk> of Hope tour . Following the first concert in San Francisco , lead singer Bono met René Castro , a Chilean mural artist . Castro had been tortured and held in a concentration camp for two years by the dictatorial Chilean government because his artwork criticised the Pinochet @-@ led regime that seized power in 1973 during a coup d 'état . Castro showed Bono a wall painting in the Mission District that depicted the ongoing plight in Chile and Argentina . He also learned of the Madres de Plaza de Mayo , a group of women whose children were forcibly disappeared by the Argentine government . The Madres ' children were students who had opposed the government during the Dirty War , and the coup d 'état that brought Jorge Rafael <unk> into power . The Madres joined together to campaign for information regarding the locations of their children 's bodies and the circumstances of their deaths , believing them to have been kidnapped , tortured , and murdered . 
