the scars of the massacre in tlatelolco square run deep. official silence over what happened here, and many see parallels between the events of 1968 and the abuses in alleged crimes by the state taking place in mexico today. this anniversary of a massacre follows quickly on the heels of another. just days ago, mexicans marked for years since the killing of 44 student teachers in iguala. like their counterparts in 1968, the victims' families face an uphill battle to uncover the truth. one student leader from battle to uncover the truth. one student leaderfrom 1968 battle to uncover the truth. one student leader from 1968 believes today's social movements in mexico must force the changes his generation was unable to. translation: when people ask me about the impact of 1968, i say we failed, because we held positions in government. we could have made a better society but failed to do so. today, mexico is on the verge of a radically different kind of president. anders manuel lopez brown. never again will the military be used to oppress the peop

a flag was lowered to half-mast in the capital city's main zocalo square tuesday to commemorate the 50th anniversary ofof the tlatelolco massacre. it was october 2, 1968, when hundreds of stududent protesters were g gunned down by soldiers s ththey held peacefeful protestsn the eve of the mexico city olympic games. this is mexican president-elect andres manuel lopez obrador speaking at a ceremony commemorating the anniversary. >> we guarantee that force will never be used again to resolve conflicts, differences, and social protest. we may, to noth repress the people. amy: just last week, a mexican government official admitted for the first time that the massacre amounted to a state crime, though no one has ever been prosecuted for the killings. this is tlatelolco massacre survivor juan avila arreaga, one of tens of thousands who marched from tlatelolco plaza on tuesday. >> my name is juan. i am 67 years old and today i came here because 50 years have passed since the soldiers opened fire on us. there were women, children, and i would like to speak about the young people, especially the students who were gunned down in