Yesterday (August 28) marked 50 years since Martin Luther King's famous 'I Have a Dream' speech during the 1963 rally of over 250,000 people in Washington DC. The speech is seen as a catalyst in the black civil rights movement, and King is often viewed as one of the greatest pacifists of modern history.
US President Barack Obama marked the occasion in Washington DC with an address from the same spot. Members of the King family and veterans of the march will also be present. Mr Obama, the first black US president, has described the 1963 protest as a "seminal event" in American history.
King made the speech in front of the Lincoln Memorial on the National Mall at 3pm local time. Obama spoke at 3pm local time just after an organised ringing of bells by churches and other groups. Former Presidents Bill Clinton and Jimmy Carter also spoke.
King's address marked the peak of a series of protests against racial discrimination that began when Rosa Parks launched the bus protests.Her action sparked a bus boycott campaign across Montgomery, Alabama.
King became a dominant force in the movement and so was called on to make the final speech at the march. He advocated the use of non-violent tactics such as sit-ins and protest marches, and was awarded the Nobel peace prize in 1964. Four years later, his assassination led to rioting in more than 100 US cities.