LONDON -- In the tiny Welsh village of Aberfan is a hillside cemetery with the graves of 116 children -- virtually a village generation -- killed one disastrous day 20 years ago by an avalanche of sludge.
For generations the menfolk of Aberfan, 170 miles west of London in hilly south Wales, gouged coal from a mine and piled its waste in a huge heap beside the village.
On fog-shrouded Oct. 21 1966, the 3 million-ton 'pit heap' collapsed with a roar. Sodden with rain and undermined by underground water, the wall of waste engulfed a primary school and a row of houses.
Five teachers and 116 pupils died in the crushed ruin of Pantglas School. Twenty-three other adults were killed.
'A generation of children in Aberfan has been wiped out,' mourned George Thomas, a Welsh government official and himself a miner's son, as parents wept over the remains of their children, many smothered to death.
The tragedy literally transformed the shape of south Wales.
Safety officials ordered changes in storing mining waste. In all, 180 pit heaps were removed outright. The remaining 170 were drained and reshaped -- some landscaped with grass, some even turned into parks.
'It led to a fundamental reappraisal,' said National Coal Board spokesman Keith Beeston on the 20th anniversary of the tragedy. 'The new regulations are such that we've done everything humanely possible to prevent another Aberfan.'
But not a day passes that the tragedy does not haunt Aberfan's 3,000 survivors. Almost one in every two families lost a loved one. One in five families there and in adjoining Merthyr Vale village lost a relative.
'An old cliche we used to hear is that time heals,' said the Rev. Kenneth Hayes, whose 9-year-old son Dryfig was killed. 'But time rarely ... no, never, heals the death of a child.'
In the hillside cemetery the 116 children have identical marble arched memorials. Villagers unceasingly place flowers on the graves of their 'lost generation.'
The tragedy 'left a generation gap of 8- to 11-year-olds,' said Ted Bartlett, 58, who lost his 8-year-old daughter, Edwina. 'For many years we saw no local engagements and weddings. It was very sad.'
Usually the sturdy Welsh villagers, including the survivors, don't talk about the tragedy. But on the anniversary a few did look back.
Susan Robertson, 28 and a mother of two, was 8 when the mountain came crashing onto the school. She still has nightmares about it.
'We heard a rumble like thunder at 9:15,' she recalled. 'Mr. Davies, our teacher who died, told us to get under the desks. There was a large crack starting to appear in the wall.
'I must have lost consciousness for a while. ... I remember them passing me through the window. ... I've never been able to forget my best friend was sitting at the next desk.'
One of her rescuers was miner Ernie Morgan, now 72. He was at home asleep when his wife woke him with the cry that 'something was wrong at the school.
'I managed to scramble (with other rescuers) through a window and into what was left of the classroom,' he said.
'One of the men found his own son crushed halfway up the classroom wall. He left his own boy there because he knew there were others alive ...
'I won't name him because I don't know whether his wife knows what he had to do -- leave his little boy there to go for the living.'
Villagers say only five families left the area following the disaster. The mine is still open.
On the site of the wrecked school, a community center was built, paid for by relief funds. Today it is plagued by financial problems.
And like the gray clouds that often hover over south Wales, the grief and tormenting thoughts of 'if only' cast a shadow on the life of the survivors.
'I still think about all those little children, going to school in their health and then dying like that,' said Morgan's wife, Joan.
'Like my friend's little girl, who said to her that morning, 'I'll have to hurry Mum, or I'll miss the bus.' If only she had.'