MIAMI, FL – APRIL 4: Hundreds march holding posters in Miami’s Liberty City neighborhood during a rally on April 4, 2012 in Miami, Florida. The rally was commemorating the death of Dr. Martin Luther King Jr. and Trayvon Martin. Martin was killed by George Michael Zimmerman who was on neighborhood watch patrol in the gated community of The Retreat at Twin Lakes, Florida. (Photo by Angel Valentin/Getty Images)