Editor's note: His “I Have a Dream Speech” is a shining example of rhetoric: poetic, beautifully-structured, full of gut-punches that make it still relevant today. It seems like the work of someone who sweated out draft after draft, but it was actually improvised in the moment. Such was the power of this great mind, of this great heart, of the great work that MLK packed into a life that was cut short at age 39. Honor one of America’s best with some beautiful Martin Luther King, Jr. wallpapers.