Parents and Relatives of some of the 43 missing students from Mexico's Ayotzinapa College Raul Isidro Burgos hold posters of them during a march to mark the one-year anniversary of their disappearance, in Mexico City, Mexico on September 26, 2015. Families of the missing and international experts cast doubt on Mexican government's official account of the incident: that municipal police handed the students over to a local drug gang who burned their bodies in a nearby garbage dump. The families asked the government to launch a new internationally supervised investigation and to review Mexico's own investigators. More than 25,000 people have disappeared in Mexico since 2007, according to the government. (Photo by Bénédicte Desrus)