The King, Queen and Prince of Wales are set to visit Aberfan later this month to mark the 60th anniversary of the disaster which killed 116 children and 28 adults.
Pantglas Junior School and surrounding houses in the village near Merthyr Tydfil, south Wales, were catastrophically engulfed in coal slurry after the colliery spoil tip collapsed on 21 October 1966.
King Charles III, Queen Camilla and Prince William will join survivors, bereaved parents and members of the community on the anniversary to pay tribute to those who died.
The royals will visit the Aberfan Memorial Garden which stands on the site of the primary school, and go to the Aberfan and Merthyr Vale Community Centre.
Late Queen Elizabeth II's reaction to the disaster in Aberfan was said to be one of the biggest regrets of her 70-year reign.
What will happen on the royal visit?
A short prayer and a moment of silence will be held in the memorial garden, and King Charles and Prince William will lay wreaths. Queen Camilla will place a posy in memory of those who were lost.
During the visit to the community centre they will meet retired emergency service workers who helped respond to the coal tip collapse, including a 96-year-old woman who was a police officer at the time.
They will also look at an exhibition that shows the huge scale of the rescue effort.
As part of their visit, the royals will spend time with former Pantglas Junior School pupils, siblings of those who died and members of the Aberfan Wives, a support group established for mothers who lost children in the disaster.
The village's Ynysowen Male Voice Choir, which formed in the aftermath of the disaster and became a support group for local men to share their experiences, will also perform.
Personal reflections will be shared from survivors and family members in the community hall, including from Jeff Edwards, who survived the disaster as an eight-year-old pupil.
Prince William will visit Ynysowen Community Primary School – which was established to carry forward the legacy of Pantglas Junior School – to unveil an Aberfan Memorial Tree.
It aims to provide a permanent place for children, families and visitors to remember the victims and reflect on the lasting impact of the tragedy.
The tree was designed and created by ArtMetal, a family-run metalwork company based in Rhayader, Powys.
The concept was developed by Ynysowen Community Primary School headteacher Simone Roden, along with Edwards who is vice chair of governors at the school.
During the early planning stages, pupils helped shape the vision of the memorial by sharing drawings and ideas.
While Prince Philip, Lord Snowdon and the then prime minister Harold Wilson visited the scene of the disaster the following day, the Queen waited eight days before going to the village, arriving to comfort the community shortly after a mass funeral had taken place.
Her former private secretary, the late Lord Charteris, previously said he felt he had given her poor advice to "stay away until the preliminary shock had worn off".
He added at the time it was the biggest regret of her reign.
But for those left mourning, there was nothing but love and respect for the Queen, who they felt helped them during their darkest hour.
In total she returned four times after her first visit during her reign, including to open Ynysowen Community Primary School in 2012.
Prince William, Prince of Wales
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