Called the "Mother of the Modern-Day Civil Rights Movement(公民権運動の母)" by the US Congress, Rosa Parks was an African-American civil rights activist who became famous in 1955 for refusing to vacate(あける、立ち退く)her seat on a municipal bus for a white man. This act of civil disobedience sparked the Montgomery Bus Boycott, which launched Martin Luther King, Jr. into prominence and became one of the largest and most successful movements against racial segregation.