ALONG with countless human lives, two millennia of Iranian history were destroyed yesterday.

The quake levelled more than half of Bam, laying ruin to its historic citadel that sits on a cliff above the city.

Built almost entirely out of mud bricks, clay straw and palm tree trunks, ancient Bam did not stand a chance.

The citadel - said to be the biggest mud brick structure in the world - included scores of ancient mud huts that were inhabited until the early 20th century.

It was believed to have been founded 2000 years ago and was an important visitor attractions. However, in the wake of yesterday's disaster, a large part of the spectacular fortified city, which sits on the outskirts of the vast Dasht-e Kavir desert, has been destroyed.

Its monuments, some of which dated from the 12th century, were contained within two square miles and surrounded by a formidable rampart with 38 towers.

Bam flourished as a site of pilgrimage and as a commercial centre during the Safavid period (1502-1722). Most of the terracotta skyline which sank to the sand yesterday is thought to date back to this era.

However, it was the city's location on the fabled Silk Road, a trading route which threaded from China, through Persia and Arabia, which transformed it into a thriving market place.

The period of prosperity, fuelled by the trade of exotic treasures from east to west, was stalled by an invasion by Afghans in 1722 and another by invaders from the region of Shiraz in 1810.

Serving as a military barracks until 1932, the citadel remained completely deserted apart from those involved in restoration work which began in 1953. Mounir Bouchenaki, a cultural heritage specialist with Paris-based Unesco, said his agency has contacted President Mohammad Khatami in hopes of dispatching an assessment team to the city.

''We will do our best to send the best experts to give their advice and support for the work of restoring this important site,'' he said.