PARIS -- For the roomful of archaeologists, scholars and Iraqi cultural officials on Friday, each neighborhood conquered in Mosul brought them one step closer to learning the fate of the ancient sites and artifacts seized by the Islamic State group.

At a two-day UNESCO conference, Iraqi officials asked for money and expertise to reclaim the cultural heritage that is on the verge of complete destruction. At sites wrenched back from Islamic State, soldiers have found trenches filled with historical treasures that were apparently intended for eventual sale, even as the extremists filmed themselves using explosives and sledgehammers to destroy ancient structures. Officials at the U.N. cultural agency said it will take years, if not decades.

“It’s not just one monument destroyed by one event. We’re talking about an entire region that has suffered for years a massive devastation,” said Francesco Bandarin, assistant director-general.

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This is what Islamic State extremists bent on destroying the symbols of history and other religions have done:

HATRA

Islamic State extremists bulldozed the ruins of this 2,000-year-old city, a day after pillaging Nimrud. A complex of temples south of Mosul, Hatra’s thick walls resisted two Roman invasions in the 2nd century A.D., only to crumble under Islamic State’s explosives. The militants are still in the area, which had been a well-preserved complex of temples south of Mosul and a UNESCO World Heritage site.

NIMRUD

Nearly 3,000 years ago, this city ruled the Middle East. Islamic State blew apart the remains of its palaces and temples. The statues of winged bulls that once guarded the site were hacked to bits and piled high. Its towering ziggurat, or step pyramid, was bulldozed in a final frenzy of destruction as Iraqi forces closed in last fall. Iraqi officials estimate it’s around 70 percent destroyed.

ST. ELIJAH’S MONASTERY



A 1,400-year-old structure on the outskirts of Mosul that survived assaults by nature and man for centuries, St. Elijah’s was razed ground in August 2014. The monastery, called Dair Mar Elia, is named for the Assyrian Christian monk - St. Elijah - who built it between 582 and 590. It was a holy site for Iraqi Christians for centuries, part of the Mideast’s Chaldean Catholic community. Only track marks remain where the monastery once stood, and the site near Mosul’s airport remains under tenuous Islamic State control.

ASHUR



The 3rd millennium ancient city of Ashur in Shirqat was the first capital for Assyrian Empire between 14th to 9th centuries BC. The militants claimed that they had destroyed some of its ruins, but they didn’t release a video as they did with other archaeological sites. Islamic State no longer controls the site, but it is not yet secure enough for archaeological experts to evaluate.

MOSUL MUSEUM



In February 2015, extremist websites showed footage of Islamic State militants with sledgehammers destroying ancient artifacts at the museum in Mosul which they referred to as idols. Iraqi archaeologists say the extremists looted the museum before trashing it. The museum is just across the river on Mosul’s west bank, practically within reach of Iraqi forces in the city.