In July 1994 the Palestinian leader, Yasser Arafat, was allowed to return from Tunisia to visit the Gaza strip, after 27 years in exile. Hear from Palestinian negotiator Saeb Erekat, who was among the crowds that were there to greet him.

(Image: Palestinian leader Yasser Arafat in the middle of a large crowd. Credit: AFP/Getty Images)

In 1953, a posthumous work by the Austrian thinker, Ludwig Wittgenstein, revolutionised philosophy. Written in a unique, sometimes poetic style, Philosophical Investigations contained new thinking about the nature of language.

Simon Watts brings together BBC archive recordings of Wittgenstein's friends and colleagues, and hears from the philosopher's biographer, Ray Monk.

(Image: Ludwig Wittgenstein. Credit: Hulton Archive/Getty Images)

The mission to save thousands of African penguins from an oil spill off the coast of South Africa in July, 2000.

Photo: Penguins make their way back to the water after being rescued from the oil slick. (ANNA ZIEMINSKI/AFP/Getty Images)

***Warning: Listeners may find parts of a personal account of this story disturbing***

In July 1986 two students were set on fire by soldiers in Chile. They were taking part in demonstrations against the military government of General Augusto Pinochet. One of the youngsters died of his wounds - the other, Carmen Quintana, survived.

Witness hears her disturbing story.

Photo: Anti government protests in Chile, April 1987. Credit: JOSE DURAN/AFP/Getty Images)

It is 150 years since a crucial battle in the American Civil War, which also inspired one of the most famous speeches in US history, the Gettysburg Address. Listen to diaries, and journals from the time.

(Image: Re-enactors portraying Union soldiers in the Murray's Brigade drill commemorating the 150th anniversary of the Battle of Gettysburg. Credit: Matt Rourke/AP)

The recent surge in violence in Iraq has echoes of the sectarian conflict in 2006-07. We hear from May Witwit, an Iraqi academic who lived throught that bloody period. She eventually fled the country, after seeing her name on a militia hit list.

(Photo: Iraqi women mourn the death of their murdered relatives, Nov 2006. Credit: AFP/Getty Images)

In June 1963 the US President John F Kennedy made a state visit to Ireland, his ancestral home. Irish novelist Colm Toibin remembers the effect he had on the people lining the streets to welcome him.

(Image: President John F Kennedy in the middle of a crowd. Credit: Keystone/Getty Images)

It wasn't until the 1950s that British researchers first connected cigarette smoking with the huge rise in people suffering from lung cancer. Initially, scientists had thought pollution was a much more likely cause. Hear an archive of Sir Richard Doll who carried out the original studies and Sir Richard Peto who worked with him.

(Image: A man holding a cigarette and blowing out smoke. Credit: Press Association)

Regarded as one of the most important pieces in 20th Century English music, it was first played in the newly built Coventry Cathedral. The original had been destroyed during World War II. Hear from one of the orchestral performers who took part, and from composer Michael Berkeley.

(Photo: Benjamin Britten in 1964 - BBC copyright)

It's 55 years since a picture of a foetus inside the womb was first published. It appeared in an article in the British medical journal 'The Lancet' on the first ultrasound scanner.