Witness

On August 25 1944 General Charles De Gaulle, who had been in exile in London for the majority of World War 2, finally entered Paris at the head of the Free French forces. But the French capital was far from secure. Ashley Byrne hears from Charles Pegulu de Rovin, who as an 18-year-old student fought with other resistance fighters against the Nazis in the final battle for Paris.(Photo by Pierre Jahan/Roger Viollet via Getty Images)

At the end of El Salvador's civil war human rights investigators began the search for hundreds of children reportedly kidnapped by the army during anti-guerrilla operations. In early 1994, two years after the end of the conflict, the first six children were located in an orphanage in the capital San Salvador. Among them was Maria Elsy Dubon, who had been seized by soldiers who killed her father in May 1982. Mike Lanchin has been hearing about Maria Elsy's distressing ordeal and about the difficult reunion she later had with her biological family, who believed that she was dead.(Photo: Peasants who lost their children during military operations in the civil war at a rally in March 2006 (YURI CORTEZ/AFP/Getty Images)

In 1998, a transponder or silicon chip was surgically implanted into the forearm of a British scientist. It sent identifying signals to a central computer that tracked his movements and allowed him access to his workplace, by opening doors and switching on lights. Professor Kevin Warwick has been speaking to Farhana Haider about becoming a more enhanced version of himself and as a result the world's first Cyborg: a man-machine hybrid.Photo: Professor Kevin Warwick with chip transponder Credit: Science Photo Library

The Dr Seuss books revolutionised the way American children learnt to read in the 1950s. Books like 'The Cat in the Hat' were designed to help young children enjoy reading simple words and sentences using rhymes, anarchic characters and lively illustrations. Claire Bowes spoke to Christopher Cerf who knew Theodor Geisel, the author of the books. Photo: Author and illustrator Ted Geisel sits at his drafting table with a copy of his book, 'The Cat in the Hat' in 1957. (Gene Lester/Getty Images)

In the 1980s Ilich Ramírez Sánchez known as 'Carlos the Jackal' was seen as the world's most-wanted terrorist. He had carried out bombings, killings and kidnappings and had been on the run for decades. He was finally arrested in Khartoum in August 1994. Alex Last spoke to former CIA operative, Billy Waugh, who tracked him down.Photograph: Rare photo of Carlos the Jackal, taken in the 1970s (AFP/Getty Images)

Throughout 2001 the US authorities were being given warnings that a terror attack was imminent. A Congressional Commission, FBI officers and the CIA were all worried. There were even specific warnings about planes being flown into buildings. Louise Hidalgo has been speaking to former Senator Gary Hart who co-chaired the Congressional Commission that tried to convince the government to take action.Photo: Smoke pours from the World Trade Centre after it was hit by two passenger planes on September 11, 2001 in New York City. (Credit: Robert Giroux/Getty Images)

The contact lens was once a precious and expensive piece of eyewear which had to be looked after and carefully cleaned every night. But that all changed in the 1990s. Ron Hamilton was involved in developing lenses and packaging which could be made so cheaply they could be worn just once and then thrown away. He has been speaking to Ashley Byrne.Photo: Ron Hamilton (l) with his business partner Bill Seden (r) and their wives with their original contact lens machine. Courtesy of Ron Hamilton.

In October 1947, an invasion of Kashmir by tribal fighters led to the division of the state between India and Pakistan. Andrew Whitehead speaks to victims of the invasion and political leaders in Kashmir to find out more about the roots of a crisis that endures to this day.PHOTO: Indian troops arriving in Kashmir in October 1947 (Getty Images)

In 1949 a British warship, HMS Amethyst, launched a daring escape after it was held captive for months by Chinese Communists on the Yangtze river. The ship had been badly damaged when it was fired on by Communist forces as it sailed up the river to help evacuate British citizens from Nanking during the final months of China's civil war. Using eyewitness accounts in the BBC Archive, we tell the story of HMS Amethyst.Photo: The HMS Amethyst (F116) arrives in Hong Kong after it's epic escape down the Yangtse. (Photo Hulton-Deutsch Collection/CORBIS/Corbis via Getty Images)

In August 1969 the British Army was first deployed in Northern Ireland. Their job was to keep the peace on the streets of Londonderry where sectarian violence had broken out. To begin with the soldiers were welcomed by residents, but attitudes soon changed and what became known as 'The Troubles' got underway.Picture: Armed British soldiers on the streets of Northern Ireland, 15th August 1969 (Credit: Press Association)

In the 1970s the UK tried to reduce its growing prison population. An experimental new punishment was introduced for convicted criminals. It was called Community Service. The scheme was soon copied around the world. Witness History speaks to John Harding, a former Chief Probation Officer, who was in charge of the introduction of Community Service in one of the first pilot schemes.Photo: BBC

In 1958 the nuclear submarine USS Nautilus travelled under the North Pole. Julian Bedford spoke to retired vice Admiral Kenneth Carr in 2012 about the mission spurred by the Cold War battle for technological supremacy.Photo: The USS Nautilus arriving in the UK. Copyright: BBC

Hundreds of thousands of French people who'd been living in Algeria for generations fled for safety to France in the summer of 1962. It was in the last days of the war of independence in the North African nation. Known as the 'Pieds Noirs', the new arrivals were not generally well-received back in France. Mike Lanchin has been speaking to Michelle Hensel, who left Algeria for France as a small child.Photo: French repatriates leaving Algeria May 1962. (Photo by REPORTERS ASSOCIES/Gamma-Rapho via Getty Images)

Thousands of Iraqi troops and tanks began pouring into Kuwait on 2 August 1990. The tiny, oil-rich Gulf state was immediately taken over by Saddam Hussein's military. Sumaya Bakhsh has spoken to Sami al-Alawi who joined the Kuwaiti underground resistance trying to free the country.Photo: Soldiers shelter behind a tank during the Iraqi invasion of Kuwait on August 2nd 1990. Credit: REUTERS.

On 1 August 1944, resistance fighters in the Polish capital rose up against German occupying forces. The uprising lasted for 63 days and some 200,000 people were killed, Warsaw itself was largely destroyed. Zbigniew Pelczynski was one of the young Poles fighting to free Warsaw from the Nazis, in 2014 he spoke to Louise Hidalgo about the battle.(Photo: Zbigniew Pelczynski in 1946)

In 1980 the Bavarian government announced plans to build a nuclear reprocessing plant in Wackersdorf in southern Germany. Eight years later construction on the plant was halted after a sustained protest campaign which saw tens of thousands of demonstrators and sometimes violent clashes with the police.Lucy Burns speaks to local district administrator Hans Schuierer, who became a figurehead for the protests.Picture: demonstrators fight against police during a protest at the Wackersdorf construction site (Istvan Bajzat/DPA/PA Images)

One of the most remarkable archaeological discoveries in British history was made in the summer of 1939, when a huge hoard of Anglo-Saxon gold was found at Sutton Hoo in Suffolk. Lucy Burns presents material from the BBC archives.Picture: the Sutton Hoo Helmet on display at the British Museum on March 25, 2014 in London, England (Oli Scarff/Getty Images)

How the death of a UK weapons inspector intensified arguments over Britain's involvement in the invasion of Iraq in 2003. Rebecca Kesby has been speaking to one of the doctors who signed a letter calling for further investigation of the circumstances surrounding Dr Kelly's death.Photo: Dr David Kelly during questioning by the Commons select committee, in London in July 2003. Credit: Press Association.

In July 2001 a team of palaeontologists led by Michel Brunet discovered a seven million year-old fossilised skull in the Djurab desert in Chad. Ahounta Djimdoumalbaye was the member of the team who first uncovered the skull which has been nicknamed Toumai. Freddy Chick has been speaking to Professor Brunet about his hunt for hominid fossils in West Africa. Photo: French palaeontologist Professor Michel Brunet, holding Toumai's skull along with Ahounta Djimdoumalbaye who discovered the skull. (Photo credit Patrick ROBERT/Corbis via Getty Images)

When Tunisia achieved independence it brought in a new equality law that revolutionised women's lives. In August 1956 under the socialist President Habib Bourguiba, the north African country became the first in the muslim world to legalise civil divorce and abortion and to ban polygamy. He also gave women the vote and widened access to education. Nidale Abou Mrad spoke to Saida El Gueyed a founding member of the Tunisian Women's Union who was asked by President Bourguiba to help both men and women understand how the new law would change their lives.Photo: Courtesy of Saida El Gueyed