In 1968, Cárdenas did not anticipate the draconian crackdown by Díaz Ordaz in the run-up to the Mexico City Olympics. That summer saw the emergence of the Mexican Movement of 1968, which mobilized tens of thousands of students and middle class supporters during the summer and early fall 1968. The movement ended in the bloody Tlatelolco Massacre on 2 October 1968. During the troubles that summer, one of Cárdenas's long-time friends, Heberto Castillo Martínez, a professor of mechanical engineering at the National University, actively participated in the movement and was pursued by Díaz Ordaz's secret police. Cárdenas hosted a meeting at his residence in the Polanco section of Mexico City with Castillo and some student leaders. Cárdenas was increasingly concerned about the impact on the movement on the political peace that had been built by the party. Despite the National University being a center of the movement, Cárdenas did not think that the government would violate the university's autonomy and take over the campus.  It did, with tanks rolling into campus on 18 September. Castillo had a harrowing escape.  In October government troops fired on demonstrators at the Plaza of the Three Cultures in Tlatelolco, someone who had been there made his way to Cárdenas's house to tell him in tears what happened. Cárdenas's wife Amalia reportedly said, "And I believe that the General shed some tears too."