Martin Luther King Jr. is known for leading the March on Washington for Jobs and Freedom, which took place on August 28, 1963. This historic event drew over 250,000 participants and became one of the largest demonstrations for human rights in United States history. King delivered his renowned "I Have a Dream" speech during this march, articulating a vision for racial equality and justice. The march was pivotal in raising awareness about civil rights issues and contributed to the passing of significant legislation, including the Civil Rights Act of 1964, which sought to eliminate racial discrimination and promote equality.