In October 1968, 10 days before Mexico City was to host the Olympics — a first for Latin America — student protests met police bullets in the Tlatelolco massacre. Fifty years later, a veteran of Mexico’s student movement reflects on what happened and the meaning of the government-student clash for Mexico and for him. Host Marco Werman speaks with Sergio Aguayo, researcher at Colegio de Mexico and a visiting professor at Harvard University.