Rosa Parks was the celebrated civil rights activist known for her pivotal role in the Montgomery Bus Boycott. On December 1, 1955, Parks famously refused to give up her seat to a white man on a segregated bus in Montgomery, Alabama. Her act of defiance became a catalyst for the boycott, which sought to end racial segregation on public transportation. The boycott lasted over a year and led to a Supreme Court ruling that deemed segregation on buses unconstitutional. Parks' courage and commitment to justice have made her an enduring symbol in the struggle for civil rights in the United States.