Try to imagine heavily armed thugs in bulldozers launching an attack on Stonehenge. They have decapitated the head of security at the site and kidnapped his family.
They then start demolishing the standing stones, smashing them to dust. They claim that what they are doing is the will of God. Imagine they film it all, to be broadcast on the internet. Imagine that - then breathe a sigh of relief that fighters from IS have not taken over Wiltshire.
Events like this are going on today at some of the most ancient sites in the Middle East.
Last summer, when Isis seized control of the northern Iraqi city of Mosul, they also took over archaeological sites as precious as any in the world.
Assyria, as northern Iraq was known in ancient times, was one of the birthplaces of civilisation. Its mudflats bear witness to thousands of years of empire-building and religious devotion. Its history is that of humanity itself. But much of it, to Isis, is a standing affront because they believe that antiquities, however exquisite, represent false idols that must be destroyed.
Last week, they duly sent in the diggers once more. Bulldozers began levelling one of the most celebrated sites in archaeology, the ancient city of Nimrud.
Founded more than 3000 years ago, Nimrud's greatest moment came in 879 BC, when the King of Assyria made it his new capital. Ashurnasirpal II was the most powerful ruler of his age. His empire covered much of Syria and Iraq. The glory of the Assyrian fills the pages of the Old Testament. 'Under his shadow dwelt all great nations.' So God tells Ezekiel. And the Bible was not exaggerating.
Treasure plundered from his neighbours enabled Ashurnasirpal and his successors to adorn Nimrud with towering statues, mighty walls and a massive palace.
He saw his remarkable city as being at the centre of the world. 'Its gates of justice pass fair judgment on the rulers of north and south, of east and west,' he boasted. 'Tribute comes from both the mountains and the sea. All of mankind bows before the city's king, their lord.'
Then, late in the 7th century BC, the Assyrian empire fell to an alliance of its enemies from what is now southern Iraq and Iran. Nimrud was laid waste. The abandoned city on the Tigris was lost to sediment, and not discovered again until 1845.
The excavator was an archaeologist and future Liberal MP named Austen Henry Layard.
The artefacts that he brought back (many of which can be seen today in the British Museum) created a sensation. There were giant winged bulls with human heads. There were exquisite pieces of jewellery. There were inscriptions written in a strange script which, when it was finally cracked, opened a window onto a great and vanished civilisation.
Photo / AP
Layard, though, had only scratched the surface of what Nimrud had to reveal. Excavations have continued to bring the glories of ancient Assyria to light.
In the Fifties, Agatha Christie joined her archaeologist husband Sir Max Mallowan in Iraq, and while at Nimrud used her face cream to clean a series of exquisite ivory carvings of lions, flowers and figurines uncovered on the site.
Then, in 1988, came the most spectacular find of all. The Iraqi Antiquities Service discovered the undisturbed tombs of three Assyrian queens beneath the royal palace. Among the goods in the graves were more than 50 kg (110 lb) of gold jewellery.
But ever since the Gulf War of 1990, Nimrud has effectively been off limits to archaeologists. Even though they were confident that further treasures remained to be discovered, no one could get at them. Now, thanks to IS, no one ever will.
There is a tragic irony here. Brilliant and sophisticated though their civilisation was, the Assyrians were also capable of terrifying brutality. Many of the atrocities inflicted by Assyria's ancient kings on their adversaries were reminiscent of IS at their worst. Royal propaganda was often the equivalent of jihadi terror videos. It boasted of burning prisoners alive, of crucifying them, of decapitating them.
The chief ministers of two kings defeated in Lebanon were forced to march through jeering crowds with the heads of their royal masters slung around their necks. Like IS, an Assyrian king would publicise these cruelties because he believed himself to be obeying the will of heaven. He was certain that he was right and his enemies were in the wrong; and that it was his duty to punish evil. So that was what he did.
From ancient times to the present day, conquerors have often been at their most destructive when they consider themselves the sword-arm of virtue. IS are not the first Islamic militia to have destroyed incomparable artistic treasures. Six months before the 9/11 attack on New York, the Taliban dynamited two monumental statues of the Buddha in Afghanistan which, in the 6th century AD, had been carved out of the side of the Bamiyan valley, and were one of the cultural glories of that nation.
Both IS and the Taliban were inspired by the example of Muhammad himself. When the Prophet conquered Mecca, he ordered it purged of all idols. A great bonfire was lit. All the various statues to be found in the city were consigned to the flames. The Devil, so it is said, cried out in anguish. Destroy a people's culture and it becomes easier to destroy the people themselves. IS have learnt this lesson well
It is not only Muslims, though, who have believed themselves mandated by God to destroy perceived idolatry. Centuries before Muhammad, Christians were busy smashing idols and closing pagan temples across the Roman world. During the Reformation, untold damage was inflicted by Protestants on the intricate treasures of medieval Catholicism.
In England, the primacy of Thomas Cromwell - recently portrayed by Mark Rylance in the BBC's dramatisation of Wolf Hall - witnessed a frenzy of vandalism. Churches across Britain still bear the scars. The statues, wall paintings and stained-glass windows that, back in the Middle Ages, had made them a riot of colour, were deliberately destroyed. As a result, almost nothing of British art from before the Reformation has survived.
Now, this kind of mass desecration of the past is happening again - but this time it is being beamed across the world almost in real time as the latest piece of slick propaganda by a group which seems to glory in its philistine brutalising of ancient beauty.Sendi
Despite its name, it would be a mistake to think that the motives of Islamic State are exclusively religious. Muslim though IS may be, they are also recognisably in a line of descent from the 20th century's worst tyrannies. 'He who controls the past controls the future,' wrote George Orwell in Nineteen Eighty-Four. 'He who controls the present controls the past.'
Orwell knew what he was writing about - he lived in a world that had been cast into deep shadow by totalitarianism. The Nazis had burnt synagogues as well as Jews. In Moscow, Stalin had ordered the Cathedral of Christ the Saviour to be levelled to the ground. From ancient times to the present day, conquerors have often been at their most destructive when they consider themselves the sword-arm of virtue.
Destroy a people's culture and it becomes easier to destroy the people themselves. IS have learnt this lesson well. Their annihilation of Assyrian monuments is paralleled by their persecution of the local Church. There have been Christians in northern Iraq almost since the time of Christ; but they trace their ultimate, geographical origins all the way back to the time of the ancient Assyrian kings. That is why they call themselves, even today, Assyrians.
The destruction at Nimrud is echoed by the ethnic cleansing of Mosul. Christian cemeteries in the region are reportedly being bulldozed. The ambition of IS is to render northern Iraq, for the first time in more than 3,000 years, free of Assyrians.
That they can achieve this while dominating the global media's news agenda shows how completely they have mastered the theatre of destruction.
A week ago, a video was released showing an IS maniac power-drilling a giant winged bull in a second Assyrian capital, Nineveh. The vandalism of such a recognisable symbol of Iraqi culture sent a clear message: archaeological significance means nothing to the new masters of Mosul.
Nineveh, too, was excavated by Austen Henry Layard in the mid-19th century. Like the giant bulls he transported back to London, reliefs from its royal palace are one of the British Museum's great riches. We must be thankful that they, at least, are out of the reach of the barbarians of Islamic State.
The second city of Iraq, Mosul was captured by IS last summer. Shortly afterwards they blew up the mosque of Jonah, the Biblical prophet who, according to Scripture, was swallowed by a whale. The mosque, built on the site of an Assyrian church, had contained Jonah's tomb and - appropriately - the tooth of a whale. Then, some months ago, IS moved on to the Mosul Museum. A recently released video showed its fighters throwing down statues and smashing reliefs - although some are believed to have been casts.
Known to the Assyrians as Kalhu, Nimrud was named by Austen Layard after the Biblical figure of Nimrod, grandson of Noah and the first man to proclaim himself a king. At its peak, between 879 and 706 BC, it was the most important city in the Middle East.
Its towering walls stretched for more than five miles, its citadel bristled with the most up-to-date military equipment, and its vast palace was guarded by colossal statues of human-headed winged bulls. Islamic State reportedly began demolishing it recently.
Founded by one of the successor kings of Alexander the Great, Hatra - a city in modern Iraq - was conquered by the Parthians, a people from northern Iran who for centuries were the Romans' most formidable rivals. Not even the emperor Trajan could conquer it. The city was a melting pot, with Mesopotamian gods, Greek temples, Arab rulers and Parthian fortifications. A temple in Hatra featured in the opening scene of The Exorcist. IS was reported to have begun bulldozing it.
A city in Syria, Apamea was expanded in 300 BC by one of Alexander the Great's henchmen. At its peak, its stables contained some 500 elephants. Conquered by the Romans, it was demilitarised and beautified.
Its ruins include an immense colonnade and a giant theatre. The remains of the city are now riddled with some 15,000 pits dug by looters. Mosaics have reportedly been dug up with bulldozers and sold on the black market.
The capital of Assyria in its final years of greatness, Nineveh was first settled more than 8,000 years ago. According to the Bible, God sent Jonah to rescue its inhabitants from destruction. Cutting-edge hydraulic engineering allowed the city to be filled with orchards and flowers: it has been convincingly argued that the Hanging Gardens were not in Babylon, but Nineveh. When British archaeologist Austen Layard excavated its palace, he uncovered 'nearly two miles of bas reliefs, with twenty-seven portals formed by colossal winged bulls'. IS fighters have been filmed power-drilling its monumental sculptures.
