Most of these belong to the Assyrian Empire in Mesopotamia that covered most of Syria and Iraq, some even dating back to the second millennium.

The Islamic State on Wednesday destroyed an iconic 840-year-old mosque and its minaret in Mosul, continuing to leave its trail of destruction even as the push to oust the IS from the city has intensified.

The al-Nuri mosque, which is also known as Mosul’s Great Mosque, is where IS leader Abu Bakr al-Baghdadi declared a ‘Islamic Caliphate’ in 2014 shortly after Mosul was overrun by the militants. The minaret, called al-Hadba, which had a leaning look like that of Italy’s Tower of Pisa had stood for more than 840 years.

IS fighters initially attempted to destroy the minaret in July 2014. The militants said the structure contradicted their fundamentalist interpretation of Islam, but Mosul residents converged on the area and formed a human chain to protect it.

The Islamic State has destroyed dozens of historically significant mosques, churches and heritage sites, claiming that their existence violated their interpretation of Islamic Law. Most of these belong to the Assyrian Empire in Mesopotamia that covered most of Syria and Iraq, some even dating back to the second millennium.

Here is a look at some of the major heritage monuments that the IS had pulled down.

Palmyra

Till date, the destruction of the 2000 year-old Palmyra remains one of Islamic State’s worst assaults on the culture and heritage of the middle-east. UNESCO called Palmyra an “oasis in the Syrian desert”. The ancient city, designated a World Heritage Site in 1980, is situated to the north-east of Damascus.

The Temple of Baal Shamin, dedicated to the Phoenician god of storms and fertilising rains, was damaged first in August 2015. Just days later, the Temple of Bel was severely damaged. Known as the “Bride of the Desert”, it was consecrated in 32 A.D.

Damage to the Arch of Triumph, built under Roman emperor Septimius Severus between A.D. 193 and A.D. 211, soon followed. The second centuryRoman theatre and the Tetrapylon were destroyed in early 2017. The Roman amphitheatre dates to the 1st Century AD and was used by the IS for public executions during its occupation of the city between May 2015 and March 2016.

The Tetrapylon, built during the rule of the Roman Emperor Diocletian in the 3rd Century AD, consisted of four sets of four pillars each supporting massive stone cornices. The monument had suffered considerable damage over the centuries and only one of the 16 pillars was still standing in its original Egyptian pink granite. The rest were cement replicas erected by the antiquities department in 1963. Now, only two of the 16 columns of the Tetrapylon remain standing.

Nineveh

Nineveh was one of the capitals of the Assyrian empire and it was the largest city in the world, according to the National Geographic. Half of Mosul is still referred to by the name. A large number of artefacts and reliefs have been excavated from the region since the 1800s, with most of them housed in museums across the world.

The Islamic State group released videos showing militants smashing Lamassu reliefs on the city’s Nirgal Gate, along with other antiquities.

The site was heavily looted and damaged by the IS sometime in 2014. The group released videos showing militants smashing Lamassu reliefs on the city’s Nirgal Gate, along with other antiquities.

Khorsabad

Present-day Khorsabad was another one of the Assyrian capitals, known as Daur-Sharrukin back in the day. Dating back to the 8th century BC, the city was attacked right after Nineveh.

A screen-grab from a video, published by the Islamic State, shows men attacking artefacts at a museum in Mosul. | Photo Credit: REUTERS TV

“[Dur-Sharrukin’s] city walls were razed, and some elements of the temples, but we don’t know the exact extent [of the damage],” Iraq’s director of antiquities, Qais Rasheed, has been quoted as saying by The Guardian. “Looting took place, and then the razing”.

The ruins of Hatra

If the destruction of Palmyra turned out be one of Syria’s biggest archaeological losses, Iraq’s culture has suffered equally at the hands of IS if not more.

IS militants ruthlessly razed the ancient city of Hatra to the ground in March 2015.

This picture shows the UNESCO-listed ancient city of Hatra, south of Mosul, on April 27, 2017. The ancient city of Hatra is one of the heritage jewels of Iraq and was damaged by IS after they took over large parts of the country three years ago. | Photo Credit: AFP

Hatra, situated in Iraq about 110 km (70 miles) south of Mosul, dates back 2,000 years to the Seleucid empire. The empire controlled a large part of the ancient world conquered by Alexander the Great. It is famous for its striking pillared temple at the centre of a sprawling archaeological site. The fortified city, which flourished in 1st and 2nd centuries AD during Parthian Empire, was home to many temples and sculptures dedicated to gods, including Apollo and Poseidon.

The excavated city of Nimrud

Less than a month after Hatra’s destruction, the city that was once the capital of the ancient world’s earliest empires was blown to bits by IS militants in April 2015.

This Nov. 19, 2008 photo released by the U.S. Army shows the statues of the lamassu, the winged, human-headed bulls that stood at the gates of the palace and were believed to ward off evil in the ancient city of Nimrud, near Mosul, Iraq. | Photo Credit: AP

Nimrud was founded in 1250 BC. Known in ancient times as Kalhu, it was capital of Neo-Assyrian empire – then the world’s most powerful state

From 879-709 BC, Nimrud was the capital of the Assyrians, one the ancient world’s earliest empires. In modern excavations, the site yielded a wealth of Mesopotamian art. In the tombs of queens were found troves of gold and jewellery. Hundreds of written tablets deepened knowledge about the ancient Middle-East.

A combo of handout satellite pictures collected on on January 12, 2016 (L) and June 3, 2016 (R), and released on June 8, 2016 by the the United Nations Institute for Training and Research (UNITAR) shows before (L) and after satellite imagery of the Nabu Temple in the ancient Assyrian city of Nimrud in northern Iraq. | Photo Credit: AFP

Many artefacts preserved in museums around world, but many remained on site. Nimrud’s winged bulls – protective deity known as Lamassu – were among best known symbols of Assyrian world. Currently the site is being ravaged by looters, with artefacts disappearing at an alarming rate even after the city was liberated.

(With inputs from Reuters, Associated Press and Graphic News)