Events are taking place across the United States today to mark the 50th anniversary of the assassination of civil rights leader Dr Martin Luther King Jr.
Dr King was shot dead by James Earl Ray as he stood on a balcony of the Lorraine Motel in Memphis, Tennessee.
He had gone to the city to support striking sanitation workers in their struggle to gain better wages and working conditions.
His death shook the United States and led to nationwide protests in a year that would also bring race riots, violent anti-war demonstrations and the assassination of presidential candidate Robert Kennedy.
Dr King’s leadership of a non-violent campaign for equal rights for African-Americans led to him being awarded the Nobel Peace Prize in 1964.
Famous for his rhetoric and soaring speeches, he came to national prominence for his campaign to end racial segregation on local buses in Alabama in the mid 1950s.
He also spoke out about housing segregation, poverty across the US and the Vietnam War.
His campaign led to major concessions but modern civil rights leaders say racism and discrimination still exist across the US.
Martin Luther King Day is a federal holiday held on the third Monday of January to mark Dr King’s birthday on 15 January 1929.
Later today, members of Dr King's family will attend a ceremony at the Lorraine motel.
Elsewhere, bells will ring at 6.01pm local time at churches, schools and universities across the US to commemorate his death.
The letter that led to Martin Luther King Jr’s Nobel Peace Prize.— The Nobel Prize (@NobelPrize) April 4, 2018
Sent in 1963 by the American Friends Service Committee, it appears the letter arrived too late. In 1964 the nomination was reconsidered and was successful. King was awarded the Nobel Peace Prize in 1964 #MLK50 pic.twitter.com/e1bOa8QPE0