Tlatelolco Massacre, Mexico City, Mexico, 1968

found: Wikipedia, Feb. 24, 2009:"Tlatelolco massacre" article (also known as the Night of Tlateloloc; in the months and weeks leading up to the Summer Olympics, there was a succession of student demonstrations; on October 2nd approximately 5,000 unarmed demonstrators at the Plaza de las Tres Culturas in the city's Tlatelolco section were surrounded by police and military forces that included tanks and armored cars; when shots were heard, the regular police and military began firing that continued for two hours)

found: NPR website, Feb. 24, 2009:"Mexico's 1968 massacre" article (thousands of students gathered on Three Cultures Square; snipers secretly placed by the Presidential Guard in surrounding buildings began firing, provoking the regular police and military to open fire, killing a number of students estimated in the hundreds)