Martin Luther King Jr.'s life was defined by several defining moments that shaped his legacy. His exposure to racial injustice during childhood in Atlanta instilled a deep sense of purpose. The bus boycott triggered by Rosa Parks' arrest marked a pivotal point, leading him to become a prominent civil rights leader. His influential "I Have a Dream" speech during the 1963 March on Washington articulated his vision for equality and justice. Additionally, his commitment to nonviolent protest and active participation in numerous civil rights actions solidified his role as a key figure in the movement for social change.