Witness: Witness Archive 2017

NTV, the only nationwide independent TV channel in Russia, was taken over in April 2001. It lost its independence despite a vigorous protest campaign mounted by its staff. Dina Newman speaks to the head of NTV at the time, Yevgeny Kiselev. Photo: Life size puppets of Russian political leaders including president Putin, on the set of NTV's popular satirical television show "Puppets"; June 29, 2000. Credit: Oleg Nikishin/Newsmakers/Getty

In April 1977, a group of disabled activists occupied a government building in San Francisco for nearly a month. The protesters were demanding the signing of Section 504 of the Rehabilitation Act, protecting disabled people from discrimination - it would be a breakthrough for the disability rights movement. Judith Heumann was one of the leaders of the sit-in. Image copyright: Disability Rights Education & Defense Fund

In April 1969 Sikh bus drivers and conductors in the northern English town of Wolverhampton won the right to wear a turban on duty after a two year campaign. One of the key tenents of the Sikh religion is that men must grow a beard and long hair secured by a comb and covered by a turban. Farhana Haider has been speaking to Avtar Singh Azad who led the campaign in the fight for Sikh religious rights. Photo Sikh bus driver 1972. Credit BBC

Tens of thousands of Polish officers were secretly executed in the USSR during World War 2. The German occupying forces reported the first mass grave, in the village of Katyn in 1943, but Moscow only admitted to the killings in 1990. Dina Newman speaks to the son of one of the murdered officers, Waclaw Gasiorowski. Photo: Gasiorowski family in Warsaw in 1936. Credit: family archive.

In the 1970s up to half a million people were killed during the brutal campaign of repression launched by Ethiopia's military regime called the Derg. Hear from one survivor who was imprisoned and tortured. Photo: Human remains. Copyright: BBC.

Israa Abd El Fattah was one of the first Egyptian activists to use social media to help organise anti-government demonstrations. In April 2008 she tried to organise a general strike in protest at low wages, and rising prices. She was given the nickname "Facebook Girl". She says the experience of using Facebook to spread the word helped activists learn how to mobilise people before the Egyptian Uprising in the spring of 2011. Photo: Israa Abd El Fattah in her office in Cairo in 2011. Credit: Khaled Desouki/AFP/Getty Images

America declared war on Germany on 6 April 1917, tipping the balance in favour of Britain, France and their Allies. The USA had resisted getting embroiled in the war in Europe for almost three years, but after the declaration of war, it sent troops to fight on the Western Front in France and Belgium. Photo: Postcard of Joseph "Black Jack" Pershing (Centre - R), the US Army General who led the American Expeditionary Force in World War I, being welcomed in Boulogne, northern France, by French General Peltier . Credit: AFP PHOTO / Historial de Péronne

In the mid-80s, the world was terrified by HIV Aids caused by a lack of understanding and misinformation. In April 1987, Princess Diana opened the UK's first purpose built HIV Aids unit at London Middlesex Hospital that exclusively cared for patients infected with the virus. In front of the world's media, without wearing gloves, Princess Diana shook the hand of a man suffering with the illness. This gesture publicly challenged the notion that HIV Aids was passed from person to person by touch. John O'Reilly was a nurse on the ward at the time of the Princess of Wales' visit. He spoke to Farhana Haider about the landmark moment in the fight against HIV Aids. (Photo: Princess Diana with an AIDS patient at the Middlesex Hospital April 1987. Credit REX/Shutterstock)

In April 1993, the Azerbaijani town of Kalbajar fell to ethnic Armenian separatists during the war over the disputed enclave of Nagorno-Karabakh. Photojournalist Khalid Asgarov tells Louise Hidalgo how he and his father were among a column of refugees who fled to safety on a two-day trek over the mountains. Picture: A refugee woman from Kalbajar comforts two of her children after escaping over the mountains in Azerbaijan, 10th April 1993. (Credit: Dima Korotayev/AFP/Getty Images)

In April 1982 the film star Jane Fonda launched her first workout video - encouraging millions of women to "go for the burn". Hear how the idea of home workouts took off, and why she felt such a compulsion to exercise. Photo: Jane Fonda on the red carpet for the Annual Academy Awards 2013. Credit: Frederic J. Brown/AFP/Getty Images

In March 2002 a massive ice shelf with a surface area of more than 3,200 square kilometres collapsed into the ocean around western Antarctica. The Larsen B ice shelf had existed for more than 10,000 years, but it split apart in a period of just 35 days. Mike Lanchin hears from the leading glaciologist Pedro Svarka who saw it happen. Photo: Satellite images showing the collapse of the Larsen B ice shelf in early 2002 (Science Photo Library)

In March 1997 the BBC launched one of the most successful children's TV programmes ever. Teletubbies was aimed at toddlers and became controversial for its use of playful language - the BBC fielded complaints from parents who feared that the 'gibberish' language used would stop their children from learning how to speak properly. Claire Bowes speaks to original cast member Pui Lee Fan, who played red Teletubby Po. PHOTO: courtesy of DHX media

In 1979, an outbreak of anthrax poisoning caused dozens of deaths in the Soviet Union. Geneticist and molecular biologist Professor Matthew Meselson and his team accessed the area years later to determine what had happened. He told Rachael Gillman about his experience. Photo: Anthrax Vial Credit: Getty Images

In 1994 the world's first genetically engineered food went on sale in the US. It was a tomato, called the 'Flavr Savr' which stayed fresh for up to 30 days. It was developed by an American biotechnology company called Calgene and Claire Bowes has been speaking to the former CEO, Roger Salquist, about the ten year journey to get the genetically engineered tomato to market. Photo: Roger Salquist, former Chairman and CEO of Calgene (courtesy of Roger Salquist)

On March 24 1980, as El Salvador edged towards civil war, a right-wing death squad shot dead the head of the Roman Catholic church. Archbishop Oscar Romero was killed by a single bullet as he said mass at the altar in San Salvador. Mike Lanchin hears from local journalist, Milagro Granados, who was there at the moment of the assassination. (Photo: A man cleans a mural of former Archbishop Romero in Panchimalco, El Salvador. Credit: Marvin RECINOS/AFP/Getty Images)

On March 25th 1975, the King of Saudi Arabia was assassinated, shot at point-blank range by one of his nephews. King Faisal's oil minister Ahmed Zaki Yamani was standing beside the king when the shots were fired. His daughter, the academic and author Dr Mai Yamani, talks to Louise Hidalgo about the impact of his death on her father and on Saudi Arabia. Picture: King Faisal of Saudi Arabia, 1967 (Credit: Pierre Manevy/Express/Hulton Archive/Getty Images)

In 1957, the Russian-born American philosopher, Ayn Rand, published Atlas Shrugged, one of the most politically influential American novels of the 20th Century. The best-seller imagines a dystopia in which all wealth-creators go on strike causing the global economy to collapse. Atlas Shrugged made Ayn Rand a hero for free-market economists and political libertarians. Simon Watts talks to Leonard Peikoff, one of Ayn Rand's earliest followers. (Photo: Ayn Rand in New York in 1962. Credit: AP)

In 1949, Soviet authorities deported tens of thousands of Estonians to Siberia. They included rich peasants and "nationalists" and their families, as well as other social groups who were viewed as a threat to communist rule. Rita Metsis was one of the child deportees. She shares her story with Dina Newman. Photo: Rita (r) and her twin sister Tiia (l) with their parents in 1940. Courtesy of the family.

During World War One, submarines began to be used widely for the first time. German submarines called U-boats tried to cut off Britain’s sea routes to starve it into submission. Alex Last presents archive recordings of the German and British submariners who risked their lives fighting in the new undersea weapon 100 years ago. Photo: Two German submarines, the U35 and U42, surface off the Mediterranean coast. (Photo by General Photographic Agency/Getty Images)

In March 1990 the left-wing politician and presidential candidate, Bernardo Jaramillo, was shot dead at Bogota's international airport. He was leader of the Patriotic Union, a party formed by members of the FARC guerrillas and the Colombian communist party. Jaramillo was among several thousand of its members killed by right-wing paramilitaries with close links to the country's drug cartels. Mike Lanchin has been speaking to the murdered politician's widow, Mariela Barragán, who was with him the day he died. Photo: Mariela Barragán and Bernardo Jaramillo (courtesy of the family)