The acclaimed cellist and conductor who became a symbol of Catalan resistance to the regime of the Spanish dictator, General Franco.

In 1943, a few hundred Jewish fighters rose up against the German army as it began its final push to erase all traces of Jewish life in the Polish capital. Krystyna Budnicka is one of the very few Jews who survived the Uprising. As her older brothers fought, she hid in a sewer beneath the ghetto.

Photo: STF/AFP/Getty Images.

In April 1975 the four-year rule of the brutal Khmer Rouge began in Cambodia.

Up to two million people are thought to have died - many summarily executed, or starved to death.

Youk Chhang survived. He was just 14 years old at the time.

(Photo: Youk Chhang, 2013)

In January 1965 Britain held a state funeral for the Prime Minister who led it through World War Two. His granddaughter Emma Soames spoke to Witness in 2011.

Photo: Press Association.

It is 70 years since a Swiss chemist stumbled upon the controversial hallucinogenic drug. His name was Dr Albert Hoffman. He thought it could be used in psychiatry but he later came to refer to LSD as his 'problem child'.

Photo: LSD tabs.Press Association.

April 1917 was one of the deadliest months for British pilots operating on the Western Front in World War One. We hear the story of a young British pilot who survived the world's first war in the air.

Photo: Dogfight over the Western Front. Hulton Collection/Getty Images.

In 1975, Lee Elder braved death threats to become the first African-American golfer to play at the prestigious US Masters in Augusta.

It was one of the last race barriers in US sport and made him a hero to many black sportsmen – including Tiger Woods.

Lee Elder speaks about the tournament to Simon Watts.

(Photo: Lee Elder playing golf later in life. Credit: Getty Images)

How severely burnt Second World War airmen learnt to overcome their terrible injuries.

They were all patients of the revolutionary plastic surgeon, Sir Archibald McIndoe at a specialist burns unit.

Two of the surviving "guinea pigs" tell their stories.

Photo: Former airmen Jack Perry (left) and Sandy Saunders.

When Mao Zedong tried to force an industrial revolution in China, millions of people starved to death. What Mao called The Great Leap Forward - led to failed harvests and famine. A journalist whose father died of starvation during that time has gathered survivors' accounts and official records to try to paint a clear picture of what happened.

Photo: hotel workers building a back yard steel smelter during the Great Leap Forward. AFP/Getty Images

*** This programme contains graphic descriptions of violence which are very disturbing ***

In the early 1980s, thousands of Zimbabweans were tortured and killed by security forces loyal to the government of Robert Mugabe during a campaign against "dissidents". We hear a survivor's story.

Photo: Troops interrogate suspect in Matabeleland 1983.