Witness: Witness Archive 2017

An ambitious ecological experiment was launched in Arizona in September 1991. It aimed to see if human beings could produce everything they needed to survive - in a man-made environment. Rachael Gillman has been speaking to Linda Leigh, one of the eight scientists who spent two years sealed inside the giant greenhouse known as 'Biosphere 2'. Photo credit: TIM ROBERTS/AFP/Getty Images

The photos taken in 1917 by two young girls were heralded by the Sherlock Holmes author, Sir Arthur Conan Doyle, as proof of the existence of fairies. Cousins Elsie Wright and Frances Griffiths were 15 and 9 when they took the photos in the village of Cottingley near Leeds in the north of England. In 1920 Sir Arthur Conan Doyle published the photos in an issue of the Strand magazine as part of an article on fairy life. He was a leading member of the Theosophical Society, a movement interested in the spirit world which had gained a following in the devastating aftermath of World War One. In 1983 Elsie Wright finally admitted that the photos had been faked. Photo: Copyright Alamy. Frances Griffiths and the "Cottingley Fairies" in a photograph made in 1917 by her cousin Elsie Wright with paper cutouts and hatpins.

A train carrying day-trippers crashed in September 1957 near the small town of Kendal, Jamaica. More than 200 passengers died and over 700 were injured. Mike Lanchin has been speaking to Earl Clarke, who was 14 years old when he survived the accident. Photo: (Alamy)

Diana's brother Earl Spencer made a passionate speech at her funeral, which was interpreted by many as an attack on the Royal Family and the British press. He speaks to Mishal Husain about delivering the eulogy - and about the "bizarre and cruel" decision that her children William and Harry should walk behind her coffin. Picture: Earl Spencer and Prince William outside the funeral ceremony for the Princess of Wales. Credit: Joel Robine/AFP/Getty Images

The online auction site first went live in September 1995. Initially, it targeted collectors of antiques and memorabilia. Soon, you could sell virtually anything on eBay. Ashley Byrne has been speaking to Jim Griffith one of the company's first employees. Photo: the eBay logo.

The novel Animal Farm was an allegory about the dangers of Soviet communism and of the communist leader Joseph Stalin. It was first published shortly after the end of World War Two, as the Cold War was just beginning. Louise Hidalgo has been speaking to Orwell's adopted son, Richard Blair, about George Orwell's work, and about his memories of his father. Photo: George Orwell with Richard on his knee in the 1940s. Credit: Vernon Richards

1983 saw a major breakthrough in the treatment of facial deformities. When the first three-dimensional reconstruction of a human head using CT scans was presented to the medical world. The images allowed plastic surgeons a far more precise way of planning surgical procedures. Farhana Haider has been speaking to radiologist Dr Michael Vannier who invented the 3D imaging technique which has revolutionised medicine. Photo: Three-dimensional CT scan of a male skull and arterial system. Credit SPL

In August 1958, Britain was shocked by nearly a week of race riots in the west London district of Notting Hill. The clashes between West Indian immigrants and aggressive white youths known as Teddy Boys led to the first race relations campaigns and the creation of the famous Notting Hill Carnival. Simon Watts reports. PHOTO: Police making arrests in Notting Hill in 1958 (Getty Images)

Germany saw its worst racial violence since World War Two in August 1992, when a home for asylum seekers was set on fire in the city of Rostock. Lucy Burns speaks to journalist Jochen Schmidt, who was trapped in the burning building.

In BBC archive recordings, veterans tell the story of how medical care dealt with the horrors of WW1. Photo: Australian wounded on the Menin Road on the Western Front, 1917 (Photo by Hulton Archive/Getty Images)

How an ophthalmologist and a dermatologist in Vancouver, Canada, discovered that small amounts of a deadly toxin could make frown lines disappear. Chloe Hadjimatheou spoke to Drs Jean and Alastair Carruthers about their breakthrough. Photo: Doctor injecting a woman's face with botulinum toxin. Copyright: Pascal Goetgheluck/Science Photo Library.

Hear from one of the German prosecution lawyers who helped put Nazi war criminals on trial 20 years after World War Two had ended. Gerhard Wiese has been speaking to Lucy Burns about the trial, and about visiting the Auschwitz death camp with other members of the court. Photo: Members of the Frankfurt court and several journalists pass through the Auschwitz camp gate with the words "Arbeit macht frei" (work brings freedom) above them. December 14,1964. Credit: Press Association.

In August 1941 one of the greatest poets India has ever produced died. Known as the "Bard of Bengal" Rabindranath Tagore was the first non-European to win a Nobel Prize for Literature and has been called one of the outstanding thinkers of the 20th century. Farhana Haider and has been listening to material from the BBC archives and hearing from Professor Bashabi Fraser, Director of the Scottish Centre of Tagore Studies. Photo June 1921, Indian poet and philosopher Rabindranath Tagore in London. Credit: Getty Images

In August 1974, Turkey ordered its troops into northern Cyprus for the second time in less than a month, leading to the division of the island into a Greek Cypriot part and a Turkish Cypriot part, a division that still exists today. Louise Hidalgo has been listening to a Turkish account of those events from the son of Turkey's foreign minister at the time, Hursit Gunes. Picture: an armoured vehicle filled with soldiers during fighting between Greek and Turkish Cypriots, August 16th 1974 (Credit: Reg Lancaster/ Express/Getty Images

The English-language newspaper was credited with standing up to Argentina's military dictatorship during the late 1970s and early 1980s. It published reports of people who'd disappeared when other newspapers were effectively silenced by the authorities. The paper's editor at the time, Robert Cox, has been speaking to Simon Watts for Witness. Photo: Argentinian soldiers frisking a civilian at a checkpoint in Buenos Aires in 1977. Credit: Ali Burafi/AFP/Getty Images.

In the 1990s students began boycotting Nike after it became linked to sweatshops. Many were horrified to find their trainers were being made by poorly paid Indonesian workers. Photo: Cicih Sukaesih telling her story in America in 1996 (courtesy of Jeff Ballinger)

For years Germans have been bathing nude at the beach. Many are members of a naturist movement called the FKK, which was banned under the Nazis and faced official disapproval during the early years of communist rule in East Germany. Mike Lanchin has been speaking to one East Berliner who recalls the heyday of naked sunbathing beside the Baltic Sea, and who still likes to bare all when he goes on holiday. Photo: Bathers enjoying the beach at Baerwalder See, Eastern Germany (Sean Gallup/Getty Images)

"We have outlawed Russia forever. We begin bombing in five minutes". It was just an unscripted joke by US President Ronald Reagan but it terrified ordinary Russians. Reagan's advisor Morton Blackwell tells Dina Newman about the president's love of anti-Soviet jokes and his determination to destroy Communism. Photo: American president Ronald Reagan in the 1980s at his desk in the White House, Washington DC. Credit: Hulton Archive/Getty Images

Nursing pioneer Florence Nightingale - known to generations as the "lady with the lamp" - died on August 13th 1910. Lucy Burns hears a recording of Florence Nightingale's voice from 1890, along with memories of her life from her great-nephew Harry Verney and her private doctor May Thorne - and Dr Rosemary Wall from the University of Hull explains her legacy in the world of public health. Recording courtesy of the Library at the Wellcome Collection Picture: Hulton Archive/Getty Images

Exactly a year before Indian independence there were deadly riots in India's second city of Calcutta. They followed mass demonstrations calling for the creation of a Muslim-majority state and persuaded many political leaders that India should be divided on its independence. Thousands of people were killed and thousands more left the city. Justin Rowlatt has been speaking to 2 survivors of the killings. Photo: Calcutta policemen use tear gas during the communal riots in the city. (Credit: Keystone Features/Getty Images)