A woman places a portrait of one of Mexico's 43 missing students on a fence outside the Mexican embassy in Buenos Aires, Argentina, Friday, Sept. 25, 2015, one day before the one year anniversary of the attack on Ayotzinapa students'. According to an independent group of experts, the disappearances of 43 students and the killings of six others were the result of a long, coordinated attack against students from the Raul Isidro Burgos Rural Normal School of Ayotzinapa in Mexico. (AP Photo/Natacha Pisarenko)
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