From Academy of Achievement:
Most historians date the beginning of the modern civil rights movement in the United States to December 1, 1955. That was the day when an unknown seamstress in Montgomery, Alabama refused to give up her bus seat to a white passenger. This brave woman, Rosa Parks, was arrested and fined for violating a city ordinance, but her lonely act of defiance began a movement that ended legal segregation in America, and made her an inspiration to freedom-loving people everywhere.
…The bus incident led to the formation of the Montgomery Improvement Association, led by the young pastor of the Dexter Avenue Baptist Church, Dr. Martin Luther King, Jr. The association called for a boycott of the city-owned bus company. The boycott lasted 382 days and brought Mrs. Parks, Dr. King, and their cause to the attention of the world. A Supreme Court Decision struck down the Montgomery ordinance under which Mrs. Parks had been fined, and outlawed racial segregation on public transportation.
More here. (Note: In honor of African American History Month, we will be linking to at least one related post throughout February. The 2012 theme is Black Women in American Culture and History).