The pivotal moment associated with Rosa Parks occurred on December 1, 1955, when she refused to give up her bus seat to a white man in Montgomery, Alabama. This act of defiance became a symbol of the civil rights movement and ignited widespread protests against segregation laws. Parks' arrest led to the Montgomery Bus Boycott, a 381-day boycott of the city’s buses, which galvanized the African American community and attracted national attention to the issues of racial injustice. Her courageous stance helped to catalyze the movement towards equality, influencing social change in the United States.