Each year on Martin Luther King Jr. Day we ask listeners to share songs about protest, peace, and justice. From Nina Simone's attack on segregation in "Mississippi Goddamn," to U2's indictment of needless war in "Bullet the Blue Sky" to Brandi Carlile's anthem of acceptance for all genders and sexual identities in "The Joke," share the songs that capture Dr. King's vision of a world where the boundaries between people are broken down. Tell us your favorites, and we'll feature them on Monday January 20, Martin Luther King Jr. Day.