To commemorate this holiday, here's "Blackbird," which Paul apparently wrote in response to the escalating racial discord that followed MLK's assassination in the spring of 1968. I actually think it's one of The Beatles' most overrated songs. For me, it never fully comes to life or blooms with color. It's just flat and rather lukewarm. But it is among Paul's better loved songs, so I'll digress for the moment.
(If the song is removed, go here).