Pictures of the Aberfan tragedy caught on camera by an American photographer will form part of a new exhibition which opens on Saturday.
Chuck Rapoport recorded the aftermath on film for Life magazine, but now his work can been seen at the National Library of Wales in Aberystwyth.
He still has vivid memories of the disaster which killed 144 people, 116 of them children, in October 1966.
They died when a mountain of waste from a coal mine crushed a school.
The national library said the stunning photographs would be shown until 18 June and then they would be donated to the library.
During a near 50-year career, Mr Rapoport, 68, has also photographed some of the icons of the 20th Century including former US President John F Kennedy, screen siren Marilyn Monroe and Cuba's leader Fidel Castro.
But it is Aberfan that Mr Rapoport remembers so well, but he nearly never made it there.
"My first impressions of Aberfan were of a dirty, black, cold and tragic place," said Mr Rapoport, speaking in Aberystwyth ahead of the exhibition.
"But I nearly didn't get there. I went into my New York office and pleaded with people there to send me to Wales.
"I was thinking as a father and knew the pictures would have a visual effect on Life's readers. I was motivated and enthusiastic about it."
With a reporter, Mr Rapoport arrived in Aberfan about eight or nine days after the disaster and stayed at the Mackintosh Hotel which is now closed.
"That was the best thing we could have done, because the hotel bar was full every night so we were able to speak to those affected," he added.
"The landlord said the bar was never usually full, but after the tragedy the men just couldn't go home - they just couldn't face it.
Mr Rapoport will donate his photographs to the national library
"Everyone had a story to tell and would get so worked up, but they would apologise and say they didn't mean to take it out on me.
"When they'd had a few drinks they would cry and say how much they missed their children.
"They told me that they couldn't go home and show their feelings to their wives because they were supposed to be the strong one."
Mr Rapoport, who was born in New York but now lives in California, added that the media had been insensitive to locals at the time.
"By the time I arrived they'd had enough of the press, but I eventually won their respect," he said.
Aberfan resident Sheila Lewis said people still remembered "Chuck."
"Some of us remember Chuck here in 1966 just weeks after the tragic disaster," she said.
"What he saw, heard and photographed clearly left a lasting impression on him. His work shows the courage and bravery of local people."
The photographer will be reviewing his book about the tragedy, Aberfan: The Days After, at this summer's Hay Festival where some of his pictures will also be on display.