Rosa Parks took crucial steps to challenge racial injustice by refusing to give up her bus seat to a white passenger in Montgomery, Alabama, on December 1, 1955. Her act of defiance became a symbol of the civil rights movement. Following her arrest, Parks was instrumental in mobilizing the Montgomery Bus Boycott, a pivotal act of nonviolent protest that lasted over a year. This boycott not only challenged segregation laws but also demonstrated the collective power of the African American community, ultimately leading to a Supreme Court ruling that declared segregation on public buses unconstitutional.