A documentary film dealing with the atrocities of the Khmer Rouge regime is opening in Cambodia.
Up to two million people are thought to have died under Pol Pot
The film, Wanting To See The Truth, includes interviews with Cambodians who describe the forced labour, starvation and mass killings under Pol Pot's rule.
But it also shows footage of young Cambodians who do not believe stories of the atrocities of the late 1970s.
The period is not taught in schools, and the producers plan to screen it to children to boost awareness.
The Khmer Rouge regime killed, starved or worked to death up to two million Cambodians between 1975 and 1979.
The BBC's Guy de Launey, in Phnom Penh, says the 35-minute film makes for occasionally staggering viewing.
Throughout the film older Cambodians describe the horrors of life under the Khmer Rouge, when up to two million died because of the regime's brutality.
The camera then pans to giggling teenagers who declare that they do not believe a word of what their relatives have just said.
Wanting To See The Truth was funded by a US-based organisation.
The film's producer, Tara Urs, said the teenagers' testimonies were evidence that times had changed.
"Our film shows a lot of people saying: 'I don't believe, I don't believe what happened'.
"But I think the better way to understand it is: 'I just have nothing in my own life today to allow me to conceive and to understand the stories of what you're telling me about what happened in the past," she said.
In the film, the young people are eventually shocked into belief when they are taken to visit the "killing fields", where they encounter vast collections of the skulls of victims.
Trials of some of the surviving leaders are due to begin next year.
Pol Pot, the founder and leader of the Khmer Rouge, died in a camp on the border with Thailand in 1998.
Other key figures have also died. Ta Mok - the regime's military commander and one of Pol Pot's most ruthless henchmen - died on 21 July 2006.