Alabama (1956)

In 1955, African-American Rosa Parks sat in a Montgomery, Alabama bus seat designated "for whites only". She was then arrested for her act of defiance. That arrest resulted in demonstrations and a boycott of Montgomery buses by African-Americans that lasted until December 1956.
Since the boycott was costing downtown stores and white businesses considerable money, negotiations where made to stop the action. But it took a Supreme Court ruling in November 1956 that segregation on transportation is unconstitutional to finally integrate the buses.
This event was also a starting point for the Civil Rights movement of Martin Luther King and others.