The old Silk Road citadel could have fallen from the pages of the Arabian Nights with its dizzying maze of streets, imposing watchtowers, ramparts, mosques and caravanserai.

"Its importance was as a well-preserved 18th-century city, preserved like a fly in aspic," said Robert Hillenbrand, professor of Islamic art at Britain's Edinburgh University.

The old quarter's inns, theological schools and bazaars collapsed in the early hours of Friday in the violent pre-dawn earthquake that local authorities reckon killed more than  20,000 people.

"Bam's importance rests with the modernisation that has destroyed most examples of the mediaeval pattern of an Iranian city with a citadel and then outlying streets," he told Reuters.

The history of the date-growing oasis town stretches back more than two millennia but the mud-brick citadel known to tourists hailed from the 18th century.

"The citadel was a photographer's dream. It is dramatic, and on a high bluff," Hillenbrand enthused.
 
Rebuilding Bam

Not all lost: The destroyed city
could cheaply be restored

Both Hillenbrand and Iranian experts said all was not lost.

"It could be cheaply reconstructed. The principal disaster is the loss of life," Hillenbrand said.

Mohammad-Hassan Mohebali, a senior restoration expert in the Iran Cultural Heritage Organisation, said Iran could rebuild the  citadel over five years for as little as 50 billion rials ($6 million).

"There are two responses: one is depression and losing hope; the other is to take into account the resources we have to restore and rebuild. I take the latter path," he told Reuters.

Cyrus Etemadi, managing director of the Caravan Sahra touring company, was distraught by the fall of the citadel.

"To me it is as if I have lost a friend I have known for 40 years," he said. "But Bam was only one of many tourist attractions, and it is not just about monuments - nature and people are prime attractions, the culture is still there."