 Complete the following phrase:  The year 1968 had seen turmoil in the United States, including hundreds of riots, both before and after the assassination of Martin Luther King Jr. and continuing after the assassination of Robert F. Kennedy. Prior to the Olympics in Mexico City in October 1968, some African Americans, led by activist Harry Edwards, had urged a boycott of the Games, but found little enthusiasm among athletes, reluctant to waste years of effort. The atmosphere was made more tense by 