Rosa Parks was an influential civil rights activist known as "the mother of the civil rights movement." On December 1, 1955 in Montgomery, Alabama, Parks refused to give up her seat to a white passenger on a segregated bus, sparking the Montgomery Bus Boycott. The 381-day boycott of the bus system was organized by the NAACP to protest segregation and resulted in a United States Supreme Court ruling that declared Alabama's segregation laws unconstitutional. Parks worked closely with Martin Luther King Jr. and helped change laws and social attitudes through nonviolent protest, risking her safety and continuing her activism even after facing imprisonment for her actions.