An entire generation was almost wiped out when 150,000 tonnes of coal waste slid down the hillside before engulfing Pantglas Junior School on 21 October, 1966.
Residents of the Welsh village attended a day of commemorative events, including a memorial service at Aberfan Cemetary at 9:15am – the time of the tragedy.
The Prince of Wales visited Aberfan and privately laid a wreath bearing the words “Er bythol gof a chyda’r cydymdeiumlad dwysaf”, meaning “In continuing memory and deepest sympathy”.
He planted a sweetgum tree in the Aberfan Memorial Garden and spoke to survivors at a reception before giving a speech, including a message from the Queen.
The message read: “As you come together as a community today to mark 50 years since the dreadful events of Friday, 21st October 1966, I want you to know that you are in my own and my family’s thoughts, as well as the thoughts of the nation.
“We will all be thinking about the 144 people who died – most of them children between the ages of seven and ten – and the hundreds more who have lived with the shock and grief of that day, summed up by one poet who said simply, ‘All the elements of tragedy are here’.
“I well remember my own visit with Prince Philip after the disaster, and the posy I was given by a young girl, which bore the heart-breaking inscription, “From the remaining children of Aberfan.”
“Since then, we have returned on several occasions and have always been deeply impressed by the remarkable fortitude, dignity and indomitable spirit that characterises the people of this village and the surrounding valleys.
“On this saddest of anniversaries, I send my renewed good wishes to you all.”
The disaster unfolded, following days of heavy rain, when excavated mining debris from the Merthyr Vale Colliery was dislodged and came thundering down the hillside.
The waste material had been piled high on the side of Mynydd Merthyr – above Aberfan – for years, even though there were numerous underground springs below.
Children in Pantglas Junior School were just getting ready for lessons when 1.5 million cubic feet of liquefied slurry crashed into the school and a number of nearby houses.
About half the children from the junior school died in the tragedy, which happened on the last day before half term. Coal bosses had been warned about “flowslides” prior to the disaster and, despite a 76-day public inquiry, no-one faced prosecution or lost their job.
And £150,000 was taken from a memorial fund for the affected families to pay for the clean-up.
This was eventually returned after decades of campaigning.
Prince Charles said “God bless you” to Marilyn Morris, 64, after hearing how she was in the last class of the senior school.
“There’s things I can remember now that I haven’t thought about until today, the 50th anniversary,” she said.