The Civil Rights Movement was a political movement advocating for the equal rights of black people.
On 1 December 1955, Rosa Parks famously refused to give up her seat to a white passenger on a segregated bus in Montgomery, Alabama, witnessed by the Thirteenth Doctor and her companions Ryan Sinclair, Yasmin Khan and Graham O'Brien. Driver James Blake called the police, who arrested her. This sparked the Montgomery Bus Boycott the following Monday.
According to Ryan Sinclair, the boycott was the beginning of a wider civil rights movement in America, led by Martin Luther King. (TV: Rosa)