Which of the following famous speeches had in 2013 its 50th anniversary?

Explanation

The American clergyman and civil rights activist Martin Luther King (1929-1968) favoured civil disobedience. He first got noticed as the leader of the 1955 Montgomery Bus Boycott. In 1964, King became the youngest person to receive the Nobel Peace Prize for his work. King is not least known for his famous words "I Have a Dream", part of a speech he gave in Washington, D.C. in 1963. King was assassinated on 4 April 1968 by James Earl Ray, aged only 39.