Each year Americans celebrate the life of the US civil rights movement’s best-known spokesman and leader on Martin Luther King Jr Day.

The movement pioneered by Martin Luther King pressured the American government to end legalised segregation in the United States.

Who was Martin Luther King Jr and why is he so important?

Born in 1929, Martin Luther King Jr was a Baptist minister best known for using the tactics of nonviolence and civil disobedience to combat racial inequality.

Mr King led the Montgomery bus boycott in 1955 after Rosa Parks was arrested for refusing to give up her seat to a white person.

Martin Luther King: Life in pictures Show all 10 1 /10 Martin Luther King: Life in pictures Martin Luther King: Life in pictures Martin Luther King Martin Luther King during his famous 'I have a dream' speech in Washington in 1963 AP Martin Luther King: Life in pictures Martin Luther King Martin Luther King Jr at the Lincoln Memorial in 1963 AFP/Getty Martin Luther King: Life in pictures Martin Luther King American civil rights campaigner Martin Luther King (1929 - 1968) arriving at London Airport. He is in England to be the chief speaker at a public meeting about colour prejudice and to appear on the BBC television programme 'Face To Face' Getty Images Martin Luther King: Life in pictures Martin Luther King Martin Luther King Jr. tells a Miami, Florida news conference, that he will go to Los Angeles to meet with black and white leaders and help create "a community of love" in the violence torn city in August 1965 AP Martin Luther King: Life in pictures Martin Luther King Martin Luther King Jr. and his civil rights marchers head for Montgomery, the state's capitol, March 21, 1965, during a five day, 50 mile walk to protest voting laws AP Martin Luther King: Life in pictures Martin Luther King An image from 1960 shows Martin Luther King at a meeting Getty Images Martin Luther King: Life in pictures Martin Luther King Martin Luther King Jr. and his wife Coretta Scott King leading freedom marchers in Montgomery, Alabama in 1965 AP Martin Luther King: Life in pictures Martin Luther King Civil rights protestors marching from the Washington Monument to the Lincoln Memorial, where the March on Washington climaxed in Martin Luther King's 'I Have A Dream' speech Getty Images Martin Luther King: Life in pictures Martin Luther King Martin Luther King and the March on Washington BBC Martin Luther King: Life in pictures Martin Luther King March on Washington – 1963 Famous for Martin Luther King Jnr’s “I have a dream” speech, the march on Washington saw 300,000 people gathering at the Lincoln Memorial calling for equal rights for African-Americans Getty

He also helped organise the March on Washington in 1963, where he delivered the “I Have a Dream” speech he is best known for.

In 1964, he received the Nobel Peace Prize for his civil rights work.

Towards the end of his life, he expanded his campaigning to include opposition to poverty and the Vietnam War.

Mr King was assassinated by James Earl Ray on 4 April, 1968, in Memphis, Tennessee, while he was planning a national occupation of Washington DC.

News of his death was followed by riots in many US cities.

Who commemorates Martin Luther King’s memory and since when?

Martin Luther King Jr Day is a paid federal holiday in the US, meaning civil servants and many school pupils are given the day off.

The day is observed on the third Monday of January each year, the day closest to his birthday on 15 January. This year, it will be held on Monday 21 January.

In 1968, Congress was presented with a petition signed by more than three million people which called for the Mr King’s birthday to be commemorated.

Atlanta, Georgia: 50 years after Martin Luther King Jr had a dream Show all 10 1 /10 Atlanta, Georgia: 50 years after Martin Luther King Jr had a dream Atlanta, Georgia: 50 years after Martin Luther King Jr had a dream georgiamlk.jpg Martin Luther King Jr Atlanta, Georgia: 50 years after Martin Luther King Jr had a dream martin-luther-king-5.jpg Civil rights protestors marching from the Washington Monument to the Lincoln Memorial, where the March on Washington climaxed in Martin Luther King's 'I Have A Dream' speech Getty Images Atlanta, Georgia: 50 years after Martin Luther King Jr had a dream martin-luther-king-4.jpg Martin Luther King Jr. sits on a couch and speaks on the telephone after encountering a white mob protesting against the Freedom Riders in Montgomery, Alabama in 1961 Getty Images Atlanta, Georgia: 50 years after Martin Luther King Jr had a dream martin-luther-king-3.jpg An image from 1960 shows Martin Luther King at a meeting Getty Images Atlanta, Georgia: 50 years after Martin Luther King Jr had a dream martin-luther-king-2.jpg Martin Luther King Jr. and his wife Coretta Scott King leading freedom marchers in Montgomery, Alabama in 1965 AP Atlanta, Georgia: 50 years after Martin Luther King Jr had a dream martin-luther-king-8.jpg Civil rights Leaders hold hands as they lead a crowd of hundreds of thousands at the March on Washington for Jobs and Freedom, Washington DC Getty Images Atlanta, Georgia: 50 years after Martin Luther King Jr had a dream martin-luther-king-1.jpg Martin Luther King Jr. and his civil rights marchers head for Montgomery, the state's capitol, March 21, 1965, during a five day, 50 mile walk to protest voting laws AP Atlanta, Georgia: 50 years after Martin Luther King Jr had a dream martin-luther-king-7.jpg American civil rights campaigner Martin Luther King (1929 - 1968) arriving at London Airport. He is in England to be the chief speaker at a public meeting about colour prejudice and to appear on the BBC television programme 'Face To Face' Getty Images Atlanta, Georgia: 50 years after Martin Luther King Jr had a dream martin-luther-king-6.jpg American president John F. Kennedy in the White House with leaders of the civil rights 'March on Washington' (left to right) Whitney Young, Dr Martin Luther King Getty Images Atlanta, Georgia: 50 years after Martin Luther King Jr had a dream georgia.jpg One vision: the Atlanta skyline

However, Republicans initially resisted the move, arguing Mr King had ties to communism and an “inappropriate” sexual past they felt the government should not honour.

But in 1983, Ronald Reagan, the US President, signed Martin Luther King Jr Day into law as an official public holiday and it was first observed three years later.

Outside of the US, it is observed in Hiroshima, Japan, with a special banquet at the mayor’s office, and Toronto, Canada, which officially recognised Martin Luther King Jr Day, though not as a paid holiday.

How is Martin Luther King Jr. Day celebrated?

Many Americans use the day as an opportunity to learn about Mr King’s life and achievements.

Others spend the day volunteering for a cause they think Mr King would have supported.

In pictures: Martin Luther King Jr's campaign for civil rights Show all 10 1 /10 In pictures: Martin Luther King Jr's campaign for civil rights In pictures: Martin Luther King Jr's campaign for civil rights 4510050.jpg Memories of a March and a Dream: Martin Luther King during the March on Washington, on 28 August 1963 AFP/Getty Images In pictures: Martin Luther King Jr's campaign for civil rights Martin Luther King and the March on Washington BBC In pictures: Martin Luther King Jr's campaign for civil rights martin-luther-king-6.jpg American president John F. Kennedy in the White House with leaders of the civil rights 'March on Washington' (left to right) Whitney Young, Dr Martin Luther King Getty Images In pictures: Martin Luther King Jr's campaign for civil rights martin-luther-king-7.jpg American civil rights campaigner Martin Luther King (1929 - 1968) arriving at London Airport. He is in England to be the chief speaker at a public meeting about colour prejudice and to appear on the BBC television programme 'Face To Face' Getty Images In pictures: Martin Luther King Jr's campaign for civil rights georgiamlk.jpg Martin Luther King Jr In pictures: Martin Luther King Jr's campaign for civil rights Picture: Library of Congress/ Wiki Commons In pictures: Martin Luther King Jr's campaign for civil rights martin-luther-king-8.jpg Civil rights Leaders hold hands as they lead a crowd of hundreds of thousands at the March on Washington for Jobs and Freedom, Washington DC Getty Images In pictures: Martin Luther King Jr's campaign for civil rights 08peoobi1.jpeg Height, far right, listens to Martin Luther King's 'I have a dream' speech in Washington in 1963 AP In pictures: Martin Luther King Jr's campaign for civil rights 4260367.jpg Beyond the 'us' and 'them' mentality: Martin Luther King's 'I Have a Dream' speech in Washington DC in 1963 AP In pictures: Martin Luther King Jr's campaign for civil rights v2-MLKAFP.jpg Martin Luther King had been imprisoned for taking his campaign of non-violent protest to the streets of Birmingham, Alabama AFP/Getty Images

Many states hold special events or lectures about race relations in the US. There is a historic walking tour in Harlem, New York, and street parades in Los Angeles.istory – will last.