When the Bam earthquake of December 2003 destroyed one of Iran's greatest sights - the ancient Bam citadel in the eastern province of Kerman near the border with Pakistan - it wasn't just Iranians who mourned its loss. The citadel was a World Heritage-listed treasure, and one that had astonished thousands of tourists.
The destruction was so absolute there are no plans to attempt to restore the magnificence of Bam. Instead the ruins of its former glories have been left as a testament to the power of nature, even over a structure that has withstood centuries of human settlement, strife and war.
It is rather poignant though that many tourist hotels and shops in Kerman province and beyond still stock guidebooks about Bam, even posters and postcards - no one really wants to let go of it.
However, a little to the east, about an hour's drive from the city of Kerman, lies a tiny adobe citadel that has a little ironically experienced something of a renaissance since the destruction of its more illustrious neighbour.
The citadel of Rayen is over 1000 years old and was slowly crumbling back into the desert until the Bam earthquake. Only then did the powers-that-be realise its worth and being an extensive programme of restoration.
Rayen may not compare with the spectacular glories of Bam but I love it for its simplicity, the very real sense of the past to be found there, and the play of light and shade on its monochrome adobe walls.
This fortified town is a now a well-preserved example of a pre-Islamic Persian city. Within its walls citizens lived in clearly defined neighbourhoods - near the outer walls lived the commoners, there was a section for the bazaar, one for the military and in one corner, within its own inner keep, the residence of the governor.
His residence is entered through a long corridor leading to a round vestibule, lit by a high clerestory. From this branch off four serpentine corridors that wind their way to the governor's own private quarters, to reception areas, and guest rooms.
At the heart of each of these quarters was an open courtyard where once flowers, fruit and herbs would have been grown around a central pool. The walls are thick adobe, with the angles and curves highlighted with white lime, creating beautiful geometrical patterns.
While Rayen's crumbing streets were once deserted, tourists are now returning and money continues to be spent on restoration. When I was here last time, in winter, there were just the two of us clambering among the houses; the only sounds the squeaking of workmen's wheelbarrows as they brought in loads of straw and clay to spread on the walls. They were carrying on with work that would have been done in much the same way millennia ago.