An hour before dawn last Friday morning, the oasis town of Bam in south-east Iran was jolted by a massive earthquake.
In the hours and days that followed, it became clear that the city, much of it made of mud-brick, had been largely destroyed.
The death toll is currently estimated at around 30,000, but it is feared that hundreds of people still lie entombed under the rubble of their own homes.
More modern buildings fared better than traditional mud brick houses
The disaster brought a flood of sympathy and relief efforts from the outside world, including from the United States, which has been at odds with the Islamic republic for more than two decades.
I have been living in Iran for the past four years and was among the first Western journalists to reach the scene of the disaster.
When visiting friends would ask me where the best places in Iran to go were, I felt obliged, of course, to mention the country's most obvious glories.
In Isfahan, they would see the glittering, highly-ornate marvels produced by the Safavid dynasty at the height of its flowering about 400 years ago.
At Persepolis, near Shiraz, they could wander around the vast and lordly ruins left by the Achaemenid empire in the 6th Century BC.
But then I would always mention Bam and urge them to go there, because to me, it had something very special and quite different about it.
Perhaps it is because it had sprung out of, and survived in, an environment that could not be ignored or resisted.
Many were left with nothing after the dust cleared
It is an oasis, with thousands of beautiful palm trees producing the dates for which it is famous.
It is set in the desert hundreds of kilometres from anywhere.
In the old days, it was a vital staging-post on the ancient trade routes linking Eastern and Western civilisations.
And it remains so today, astride the main international road from Iran to Pakistan.
What was fantastic about it was, of course, the city's heart: the citadel and the walled, largely medieval town which grew up around it.
With its bastions and crenellated towers, its domes and arches and alleyways, it was the biggest mud brick structure in the world.
It was a wonderful place to wander and fantasise about the past. Its accretions of centuries went back something like 2,000 years, but you felt that here was a place, divorced, neither from its past, nor from its environment: at one, with both time, and place.
It seemed close to the essence of life, growing out of the very soil in which it stood.
Bam's rich history and architecture will be rebuilt, leaders have said
And of course, around the old city had grown up the new, housing about 80,000 people.
Most of this, too, was made of mud brick warrens, usually not more than one or two storeys high.
There had been a strong tremor at around 10pm the previous evening, making some people nervous enough to sleep outside despite the cold.
One survivor we met, Ali, told us how he tricked his own family by telling them there had been a broadcast ordering people to sleep in the open, so they did. He had a premonition.
He was right.
Just a few hours later, the earthquake struck.
In the space of about 10 seconds, the citadel, the old city, and huge areas of the new quarter of Bam, were reduced to jumbled oceans of dust and rubble.
Ali and his family survived.
But still uncounted thousands of others were simply buried as they slept.
The very mud brick, which had brought life to Bam, now brought it death, and on a massive scale.
Unlike modern reinforced concrete buildings, collapsing mud brick disintegrates into densely-packed mounds of rubble: there are no big slabs to create pockets and spaces where people might cling to life.
Struggle to survive
So after the first big wave of survivors were retrieved in the first day or two, the story was one of a diminishing handful of miracle survivals.
Almost always, it was the same grim story of whole families being dug out dead, one-by-one, from where they had been sleeping.
And then re-interred, hundreds at a time, in trenches being dug at the local cemetery.
One particular moment that got to me, and it was a random one, was watching the limp body of a young girl, perhaps 10 or 11 years old, being pulled from the rubble by relatives.
The men were sobbing loudly and openly, the women wailing inconsolably.
Most people in Bam have lost a relative or someone they know
I imagined the girl in life, scampering among the palm trees, and imagined how I would feel if this were one of my own daughters.
It was hard to perform for the necessary correspondent's "piece to camera" after that.
One of the moving things about such horrendous disasters is the human response it brings.
Within little more than a day, hundreds of search-and-rescue experts from at least 26 different nations were already hard at work alongside thousands of Iranians trying to save lives in this remote desert oasis many had never heard of before.
Among them, of course, were around 80 Americans.
Both Tehran and Washington had agreed to set aside 25 years of hostility for the occasion, producing speculation that "earthquake diplomacy" might succeed in melting the political ice.
There is an outside chance that it might, though hardliners here, chanting "Death to America" again at Friday prayers just a week after the disaster, are clearly bent on stopping it.
As for Bam itself, there are official pledges to rebuild the citadel.
But it will be a reconstruction, and never quite the same thing. With enough effort and money, the city of Bam can be reconstructed too, along with the lives of the survivors.
But those lives too, all of them deeply touched by this tragedy, will also never be the same.
From Our Own Correspondent was broadcast on Saturday, 3 January, 2004, at 1130 GMT on BBC Radio 4. Please check the programme schedules for World Service transmission times.