The anniversary of the Aberfan disaster will be marked by quiet reflection in the village.
A time to remember those who were lost and to give thanks for those who survived. A time, too, to look to the future, for a community that lost almost a whole generation.
Rescuers came from all over Wales, but many children perished
After a public service on Thursday evening, a very private memorial for family and friends will take place on the mountainside cemetery above Aberfan on Saturday, exactly 40 years after so many lives were marked by tragedy.
There they will lay wreaths and say prayers to remember the 144 people who died as a coal waste tip slid down the mountain engulfing almost two dozen homes and the local junior school. Of the dead, 116 were children.
It was misty that morning in the mining village near Merthyr Tydfil. The children were looking forward to breaking up for half-term.
But at 0915 the village heard a dreadful sound that was to haunt the community - and indeed a nation - for a lifetime.
Gaynor Madgewick was eight years old and had just sat down to a maths lesson at Pantglas Junior School.
"We heard a terrible, terrible sound - a rumbling sound - it was so loud. We just didn't know what it was," she said. "It seemed like the school went numb. I was suddenly petrified.
"It got louder and louder. I remember thinking: 'Something terrible is going to happen.' Then it just went black. I tried to run for the door but I never made it.
Gaynor Madgewick woke up in the darkness to a 'terrible nightmare'
"Next thing I remember is waking up to a terrifying nightmare. There was chaos, debris everywhere, children everywhere. A couple of my mates were lying underneath me and at the side of me. One little boy - a friend - died at the side of me."
Hettie Williams was teaching in a nearby classroom when she heard the "indescribable" noise.
She said: "I said to the children: 'Quick, get under the desks, something's coming down on top of us.'
"Then the walls started to crack. I opened the door and it was just black outside. I could see some light. There seemed to be a tunnel. I said to the children: 'It's fire drill, don't look left or right' and they just crawled out through this tunnel."
All her pupils escaped, but the scene elsewhere was much bleaker. "There were 34 children in my class - only four survived," recalled former pupil Jeff Edwards.
"I walked to school as normal that morning with my best friend Robert - minutes later he was dead.
"One minute I was a child walking to school kicking a ball without a care in the world. The next, I had death on my shoulder."
As the news broke, rescuers came from everywhere. Miners from the local pit marched through the village to find the school engulfed and firemen were summoned from all over Wales.
Hundreds just threw a spade in their car and drove to Aberfan, desperate to help. As they dug through the still-moving slurry, every now and again a rescuer would shout out.
A whistle was blown and silence descended as they listened for any hope, any tell-tale sign of life.
But within two hours all hope had gone. Nobody was rescued after 1100 that morning. It was a week before all the bodies were recovered.
Sorrow soon turned to anger. The National Coal Board, which owned the mines and tips, tried to claim it was an act of God.
Lord Robens, the board's chairman, blamed a natural spring which had been pouring water into the heart of the tip, but said it was impossible to know it was there.
That was untrue however. It had been common knowledge in the village. People had previously voiced fears about the tip's safety.
Conclusions from a tribunal of inquiry set up to investigate the disaster were scathing. The coal board was condemned for its weaknesses and failures, the government criticised, but no one was ever prosecuted, fined or dismissed
The disaster caused an outpouring of grief, and £1.75m flooded into the village. Then came the second blow.
Afraid the tips that remained could slip again, the villagers wanted them removed. When their demands weren't met they dumped bags of slurry in the Welsh office.
The memorial park was built on the school site
The government finally agreed they should be removed, but the village had to pay £150,000 from the disaster fund towards the work.
Professor Iain McLean has carried out extensive research into the disaster and studied at length the findings of the inquiry. He says: "This was a disaster waiting to happen. So many lessons should have been learnt and were not.
"I was scandalised by the behaviour of Lord Robens and chiefs of the coal board, the failure of anyone in authority to understand the traumas of the people of Aberfan and the failures of the government - the most notorious forcing the fund to pay for the removal of the tips."
The cash was eventually repaid 30 years later but without interest payments, and is money the village says is now needed to maintain the graves.
The pain is still as tangible today. But the villagers don't dwell on the past and they have launched many projects to bring new work and hope to the area.
Many don't want to speak about their loss and are more keen to talk about rebuilding a future in the village.
The disaster caused division amongst those who lost family and those whose loved ones survived, a split that time has helped to heal.
Cliff Minett fully understands this. While his daughter Gaynor Madgewick was pulled out alive, another daughter and son died at the school that day.
"Saturday is no different from any other day for us," he says. "It doesn't matter if it's one year or 40 years on - the pain is just the same, the memories as clear today as they were then.
"Some will go the cemetery to remember - others will stay at home, but we will never be able to forget what happened in Aberfan that day."