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.

Photo: Anthrax Vial

In 1994, biotech company Calgene brought the world's first genetically modified food to supermarket shelves.

The Flavr Savr tomato kept fresh for 30 days and could be shipped long distances without going off.

Yet the world was wary of this new food, and it took 10 years and $100m of investment to get it to market.

In 2017, Calgene's then-CEO Roger Salquist told Claire Bowes about his mission to revolutionise the world's food.

(Photo: Roger Salquist with a crop of Flavr Savrs. Credit: Richard 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)

In March 2001 thousands of sex workers gathered in the Indian city of Kolkata for a festival organised to improve their rights and counter the stigma they faced. Sex worker groups across the world now celebrate this day in March as an annual event. Farhana Haider has been speaking to a former prostitute, Bharati Dey, who took part in the gathering.

Photo: Sex workers from around the world relax during the Sex Workers' Freedom Festival in Kolkata 2012. Credit: DIBYANGSHU SARKAR/AFP/Getty Images