It is nearly 50 years to the day since the Aberfan mining disaster which killed 116 children and 28 adults.
And mothers who lost their children that fateful day have told their stories in a new documentary which sees some of them speak publicly for the first time.
Marilyn Brown, who lost her 10-year-old daughter Janette, said her daughter didn't want to go to school that day - there was only one day to go until half-term.
"I can see her now waving back," she said.
It was Marilyn's nephew who alerted her to what had happened.
She said: "He came running in and said 'I think you had better get up the school, something's happened.'
"When I got up there it was very, very quiet.
"A lot of women standing there, very sad, some were crying as well.
"And then some of the women were up on the rubble by the school, passing bricks to one another. It was unreal."
Pat Lee, whose eight-year-old daughter Ann was killed, said: "They had the children in the chapel and you had to go in to identify them.
"I couldn't do it, I couldn't go in. So my husband went in, and his brother.
"I remember him coming out and asking what she had on. It's hard to explain to be honest.
"How you feel if you, suddenly your eight-year-old child who is beautiful, and she is gone. It was a nightmare really. I don't think I existed, then."
The deaths devastated the Welsh village and in the wake of the catastrophe a group of mothers came together to comfort each other.
They later became known as The Aberfan Young Wives.
The majority of the women were in their mid-thirties and all had lost children that day.
And 50 years later they still meet each week to remember their loved ones.
What is the Aberfan disaster?
On the morning of 21 October 1966, 100,000 tonnes of coal waste from the local mine collapsed down a mountain in the village of Aberfan in South Wales.
The slurry covered the primary school and houses below in minutes killing 116 children and 28 adults.
In the hours and days that followed rescuers dug through thick rubble in a desperate attempt to save lives - but only a handful of children survived.
If tragedy had only struck a few minutes earlier the children would not have been in their classrooms - or a few hours later when they would have broken up for half-term.
The spill was caused by a build-up of water following days of torrential rain.
An official inquiry blamed the National Coal Board for extreme negligence and it led to new leglislation being passed about public safety for mines and quarries.