Martin Luther King Jr.'s legacy is most closely associated with the Civil Rights Movement in the United States, particularly his leadership in the struggle against racial segregation and discrimination. His advocacy for nonviolent protest and civil disobedience led to significant legislative changes, including the Civil Rights Act of 1964 and the Voting Rights Act of 1965. King's famous "I Have a Dream" speech during the 1963 March on Washington galvanized public opinion and continues to resonate as a powerful symbol of the fight for equality. His work laid the groundwork for future civil rights efforts and inspires movements for social justice around the world.