The civil rights leader Martin Luther King Jr. waves to supporters on Aug. 28, 1963 on the Mall in Washington D.C. (Washington Monument in background) during the "March on Washington." (Image credit: CNP/Getty Images) Martin Luther King Jr. was a pastor, humanitarian and leader in the American civil rights movement of the 1960s. In numerous speeches, marches and letters, he fought for racial and economic justice and was lauded for his nonviolent approach to civil disobedience. Assassinated in 1968 at the age of 39, King made an incredible impact on the country's racial, cultural and intellectual landscape. Martin Luther King's...