 U2 debuted " Mothers of the Disappeared " on 14 April 1987 in San Diego , California , on the first leg of the Joshua Tree Tour , where it closed the concert in place of the band 's long @-@ time finale " 40 " . It was performed three more times on the leg ; twice to open the encore and once to conclude the main set . U2 revived the song seven months later on the third leg , playing it in the encore at three of the final four concerts on the tour . 
