Key moment: An unidentified woman rides a bus as a Freedom Rider in 1961.
Historical significance: Student activists from the Congress of Racial Equality launched the freedom rides to protest segregation on buses and trains across the South. Riders encountered violence, leading to tensions with older activists who called for an end to the rides. But students opposed the idea: “We can’t let them stop us with violence,” student Diane Nash said, according to one account. “If we do, the movement is dead.” Throughout the summer and fall of 1961, men and women joined the freedom rides, which ended after a federal ban against segregation took effect in September 1961. (Photo courtesy Hirshhorn Museum and Sculpture Garden/Smithsonian Institution)