Today in Music History for Jan. 21: In 1891, Calixa Lavallee, the composer of ``O Canada,'' died from tubercular laryngitis at his home in Boston. He was 48. In 1902, ``The Ode to Newfoundland'' was ...

From J. Cole to Public Enemy, these 15 tracks show how artists keep Martin Luther King Jr.’s name alive in Hip Hop and R&B.