The African-American lab technician, Vivien Thomas, whose surgery helped save the lives of millions of babies but whose work went unrecognised for years. Claire Bowes has been listening to archive recordings of Vivien Thomas describing his long partnership with Dr Alfred Blalock, the man solely credited with inventing an operation in 1944 which helped manage a congenital heart defect called Tetralogy of Fallot.

(Photo: Vivien Thomas, US Surgical Technician, 1940)

In 1951 cells taken from an African American woman suffering from cancer were found to be unique because they carried on reproducing endlessly in the laboratory. Henrietta Lacks died of cervical cancer in 1951. Cultures from her cells have since been used to provide medical breakthroughs but as Farhana Haider reports, Henrietta Lacks was never asked if her cells could be used in medical research.

(Photo: Henrietta Lacks. Copyright: Lacks Family)

The epic mini-series about slavery in the USA hit TV screens in January 1977. Based on a novel by Alex Haley it imagined the lives of his ancestors who had been brought to the US from Africa on slave ships. It revolutionised perceptions about African-Americans and their history. Ashley Byrne has spoken to Leslie Uggams who played the character Kizzy in the series.

(Photo: Actors LeVar Burton, Todd Bridges and Robert Reed in Roots. Credit: Alamy)

In December 1976 unidentified gunmen tried to kill Bob Marley at his home in Kingston, Jamaica. The legendary reggae singer miraculously survived with just light injuries. Mike Lanchin has been hearing from Nancy Burke, one of Marley's friends and neighbours, who was trapped inside the house as the gunmen stormed in, guns blazing.

Photo: Bob Marley, 1970s (Michael Ochs Archives/Getty Images)

In November 1950, Clarence Adams, an African-American soldier fighting in the Korean war, was captured by the Chinese Red Army. He was held in a prisoner of war camp until the war ended. But instead of returning home, Adams and 20 other GIs chose to settle in China. Rob Walker has been speaking to his daughter, Della Adams.

(Photo: Clarence Adams and his Chinese wife, Liu Lin Feng, courtesy of the family)

Just three days after the 9/11 attacks on America, Congress gave the President the power to order military action against any person, organisation or country suspected of involvement in the attacks - without needing Congressional approval.

Witness speaks to Congresswoman Barbara Lee, the only member of the legislature to oppose the new powers.

Photo: Barbara Lee in 2002. Credit: Getty Images News.

In August 1969, Arthur Mitchell founded the Dance Theatre of Harlem - the first classical ballet company to focus on black dancers. Virginia Johnson, now the organisation's director, was a founder member.

(Photo: The Dance Theatre of Harlem, circa 1970. Virginia Johnson pictured back row, third from left. Credit: Marbeth)