It is 30 years since a British scientist found out how to identify individuals by their DNA. Professor Alec Jeffreys of Leicester University remembers the eureka moment that changed police investigations forever..

Photo Credit: Leicester University.

The Chinese communist leader Mao Zedong died on 9 September 1976. Among those jockeying for power after his death, was his widow Jiang Qing. American, Sidney Rittenberg, remembers her rise and fall.

(Photo: Jiang Qing (right) alongside Mao Zedong in 1967. Credit AFP/Getty Images)

Pakistan declared that members of the Ahmadiyya sect were not Muslims in September 1974. Thousands of Ahmadis were forced from their homes, many were killed in communal violence. Witness speaks to Abdul Bary Malik and Mohammed Ashraf - two Ahmadi men who lived through that time.

Image: Photos of Pakistani Ahmadis murdered in communal violence (Getty Images)

In September 1987 the authorities in Myanmar suddenly announced that most of the banknotes in circulation in the country were invalid.

The decision, made without warning, had been ordered more or less on a whim by Myanmar's leader General Ne Win. He was a superstitious man and withdrew all 25, 35, and 75 kyat notes because they were not divisible by nine.

Farhana Haider reports on the chaos that ensued.

(Photo: AFP/Getty Images)

Kitty Hart-Moxon and her mother were sent to the Nazis' most notorious death camp in April 1943. More than a million people died in Auschwitz. Kitty tells Witness how she and others survived.

Photo: Family at the raiway terminal of Auschwitz-Birkenau concentration camp, probably taken May-June 1944 (AFP/Getty Images)

In September 1958 the first Russian-language edition of Boris Pasternak's famous novel Dr Zhivago was published - not in the Soviet Union, but in Europe. Pasternak had entrusted his novel to a handful of foreigners, after it became clear the Soviet authorities would refuse to publish it. We talk to the Italian journalist Sergio d'Angelo who first smuggled out the manuscript of Pasternak's last masterpiece and tells us how the Soviet authorities tried to get it back.

Photo: Boris Pasternak, the Russian poet and novelist, in 1946, Credit: Keystone/Getty Images

In September 1964, a ground-breaking new boutique called Biba opened in Swinging London. Witness speaks to Biba creator Barbara Hulanicki.

Picture: 30 September, 1966 - two sets of identical twins who work as shop assistants at Biba's boutique in Kensington, west London (left to right Rosy Young, Nicole Hellier, Michelle Hellier and Susy Young.) Photo by Caroline Gillies/BIPs/Getty Images.

At the start of World War One, British and German colonial forces went into battle in East Africa. Tens of thousands of African troops and up to a million porters were conscripted to fight and keep the armies supplied. We hear very rare recordings of Kenyan veterans of the King's African Rifles, talking about their experiences of the war. The interviews were made in Kenya in the early 1980s by Gerald Rilling with the help of Paul Kiamba.

In the summer of 1978 a British woman, Janet Parker, became the last known victim of the deadly virus smallpox. Witness speaks to Professor Alasdair Geddes, who diagnosed Mrs Parker.

(Image: Science Photo Library)

In the summer of 1964 writer Ken Kesey and his Merry Band of Pranksters set off on a psychedelic journey - experimenting with LSD while driving across America in a converted school bus. Immortalised in the book The Electric Kool Aid Acid Test, their trip would become one of the defining moments of American counterculture. Witness has been speaking to surviving Prankster Ken Babbs.

Picture: Ken Kesey on April 24, 1997 in Springfield, Oregon, with his bus, 'Further' (AP Photo/Jeff Barnard, File)