Videos of ISIS militants destroying priceless artifacts and world heritage sites have sparked a new level of outrage around the world.

This week, Iraqi officials reported that ISIS bulldozed parts of the ancient city of Khorsabad. The revered sites of Nineveh, Nimrud and Hatra - all of which are either designated or nominated to be UNESCO World Heritage sites - have been attacked by the caliphate. Above, you can listen to Brent Bambury's interview with Amr Al-Azm, who is working with a group dubbed the Syria's Monuments Men. They are an anonymous group of archaeologists, curators and activists who tread into dangerous territory to document what's been lost and try to preserve sites in danger. Below is a list of some of what's been lost.

Ten historical sites destroyed by ISIS and why they matter

1. Khorsabad

Ancient Assyrian site of Khorsabad (Dun Sharrukin), founded by Sargon II. (Getty Images/Lonely Planet Images)

2,700 year-old-city in northeastern Iraq, known for its colossal statues of winged bulls with human heads.

Known damage: Iraqi antiquities director Qais Rasheed told Reuters: "The city walls were razed, and some elements of the temples, but we don't know the exact extent (of the damage). Looting took place, and then the razing,"

Why it matters: Assyrian King Sargon II built his palace here between 717 and 706 BC. Paint was still preserved, as was written documentation about how its construction was organized. Some of the carvings of the winged bulls were shipped to Europe and the US in the 19th century, but experts say they were only a fraction of the artifacts at the site.

2. Assyrian Lion Statues

These lions were seated at the entrance gate of Arslan Tash. Both lions were destroyed after they were bulldozed in April 2014. (Heritage for Peace) (Heritage for Peace)

Originally from the Arslan Tash archaeological site near Aleppo in Syria, they'd been moved to Raqqa city centre in the 1980s.

Known damage: Destroyed by bulldozer

Why they matter: The statues date to the 8th century and were seated at the entrance gate of Arslan Tash, which was conquered by the Assyrians in 9th century BC and had been part of an Iron Age kingdom.

3. The winged bulls at Nineveh

(Getty Images)

Standing at the Nergal Gate at Ninevah for nearly 3,000 years, near Mosul, Iraq.

Known damage: at least partially damaged by power tools

Why they matter: Also known as "lamassu", the winged bulls date to the early 7th century BC and guarded a principal gateway to the ancient Assyrian capital of Nineveh. Other winged bull statues still exist, but it was rare that they'd remain in-situ (as opposed to being relocated to museums) as these did at the Nergal Gate. According to UNESCO, Nineveh "was one of the most important cultural centres in the ancient world enjoying a prominent role in the field of developing human civilization, in that it was the greatest metropolis where various branches of arts and learning originated."

4. Mosque of The Prophet Younis (Jonah's Tomb)

People walk on the rubble of the destroyed Mosque of The Prophet Younis, or Jonah, in Mosul, 225 miles (360 kilometers) northwest of Baghdad, Iraq. (AP Photo, File) (The Associated Press)

Located in Mosul, Iraq, near the walls of Nineveh.

Known damage: destroyed

Why it matters: Believed to be the burial place of the prophet Jonah, who was swallowed by a whale in stories from both the Bible and the Koran. It was built on an archaeological site dating back to 8th century BC and attracted religious pilgrims from multiple faiths around the world.

5. Sufi Shrines

Destroyed Sufi Shrine (Heritage for Peace)

Located in the Aleppo countryside in Syria.

Known damage: many destroyed

Why they matter: Sufi shrines are the tombs of Sufi saints. Shrines on the eastern Aleppo plateau have been destroyed, including the tomb of Meqam Shiekh Aqil al Manbaj, an important Muslim mystic. Tombs along the road to Najim Castle as well as in front of the castle have been destroyed and those part of archaeological Tells north of Aleppo have been bombed.

6. Nimrud

Egyptian Winged Genius. Ivory artefact from Nimrud, Iraq. Assyrian civilization, 8th Century BC. (Getty Images/DeAgostini)

The ruins of an ancient city located on the Tigris River just south of Mosul in Iraq.

Known damage: at least partially ruined by bulldozers and heavy military vehicles

Why it matters: Nimrud was founded in 13th century BC and was the capital of the neo-Assyrian empire. The site contains the palace of Ashurnasirpal, the king of Assyria, and large numbers of relics and statues still remained in their original locations. UNESCO condemned the attack as a "war crime."

7. Mosul museum

Islamic State militants take sledgehammers to an ancient artifact in the Ninevah Museum in Mosul, Iraq. (AP Photo via militant social media account) (AP)

Iraq's second-largest museum, located in Mosul, Iraq.

Known damage: the contents of at least two rooms were destroyed with sledgehammers and by other methods

Why it matters: The museum houses relics from the UNESCO World Heritage site of Hatra, as well as artifacts from Nineveh. Though experts say that at least some of the pieces destroyed were replicas, one treasure appears to have been lost, a 7th century winged bull that once stood at the gate to Nineveh

8. Hatra

The Great Temple of Hatra. (Getty Images/Lonely Planet Images)

2,300-year-old city south of Mosul, Iraq.

Known damage: looting; large statues destroyed or defaced; destruction of city itself underway

Why it matters: Hatra is a UNESCO World Heritage site. It consists of a well-preserved complex of temples that blend Hellenistic and Roman architecture with Eastern decorative features. Thanks to its high walls and towers, the city withstood invasions by the Romans in AD 116 and 198.

9. Mari

Sacred enclosure of Mari (Tell Hariri), Syria, Mesopotamian civilization, 3rd - 2nd millennium BC (Getty Images)

An ancient Bronze Age site located on the western bank of the Euphrates River near Syria's border with Iraq

Known damage: severely looted; satellite imagery shows over 1,200 pits dug into this once-intact site

Why it matters: Remains date back to 3000 BC. Large numbers of paintings and artifacts were discovered when archaeological digs began in the 1930s. But the site's greatest treasures are thought to be the thousands of clay tablets that describe the civilization's legal system, economy and diplomacy.

10. Tell Ajaja and Tell Brak

Photo of an artifact discovered during illegal excavation at Tell Ajaja archaeological site, and whose location is unknown. (Department of Antiquities of Hasaka; Heritage for Peace)

Ancient settlement mounds in northeastern Syria

Known damage: both looted and destroyed, according to experts

Why it matters: The sites contained large Assyrian statues and relics believed to be 3000 years old.