Following Rosa Parks' arrest on December 1, 1955, for refusing to yield her bus seat, approximately 40,000 Black residents of Montgomery, Alabama, began a 381-day boycott of the city's segregated bus system. The Montgomery Improvement Association, led by 26-year-old pastor Martin Luther King Jr., organized carpools and sustained the protest despite bombings and mass indictments. On November 13, 1956, the U.S. Supreme Court ruled bus segregation unconstitutional, and Montgomery's buses were desegregated on December 21, 1956.