Martin Luther King Day marked across the US - in pictures

The Martin Luther King memorial in Washington. The memorial opened last year after more than 20 years in the pipeline Photograph: Evan Vucci/AP

The Rev Al Sharpton, centre, with activist Dick Gregory and Washington mayor Vincent Gray Photograph: Evan Vucci/AP

A woman touches the memorial in Washington. Fourteen of Dr King's most famous quotes are inscribed in the granite Photograph: Evan Vucci/AP

Barack Obama, first lady Michelle and daughter Malia pause to mark Dr King at the Browne Education Center in Washington Photograph: Mike Theiler/Getty Images

Vice-president Joe Biden at an event at Girard College in Philadelphia Photograph: Joseph Kaczmarek/AP

Union Station in New Haven, Connecticut. More than 100 people gathered in New Haven to remember Dr King Photograph: Timothy A Clary/AFP/Getty Images

Occupy the Dream demonstrators march to the Federal Reserve from the African Burial Ground national monument in lower Manhattan Photograph: Michael Nagle/Getty Images

'There is no stopping point short of victory' – taken from a speech King gave in Memphis on 3 April 1968 Photograph: Michael Nagle/Getty Images

Prayers at the African Burial Ground national monument Photograph: Michael Nagle/Getty Images

The Martin Luther King statue in Birmingham, Alabama, where the Birmingham campaign – a non-violent direct action strategy designed to highlight the unfair treatment of black people – took place Photograph: Joe Songer/AP

Occupy the Dream demonstrators in New York. Ronald Reagan signed Martin Luther King Day into law in 1983 Photograph: Michael Nagle/Getty Images

A celebratory parade in Washington Photograph: Brendan Smialowski/Getty Images