There are 10 world heritage sites in Iraq and Syria. Nine are in danger

Satellite imagery released by the United Nations this week has confirmed that the Islamic State destroyed one of the most important ruins in the ancient city of Palmyra over the weekend.

The destruction of the 1st-century Temple of Bel appears to be part of a broader campaign by the group against not just Palmyra but a variety of ancient sites -- a campaign that appears to be motivated by both ideology and greed. Worse still, the Islamic State is only one part of a wider situation in Syria and Iraq where a number of important historical areas are considered at risk.

The situation is stark. The United Nations Educational, Scientific and Cultural Organization (UNESCO) lists 10 world heritage sites in Syria and Iraq. Of those 10, it says nine are currently in danger — and not just because of Islamic State vandalism.

Here are descriptions of the sites in danger:

Palmyra

The ancient city of Palmyra was once one of the most well-known tourism spots in all of Syria. The site, which predates Islam by hundreds of years, had become a center for trade by the 1st century A.D. -- its existence is even recorded in biblical texts. It has been controlled by the Islamic State since May.

"The art and architecture of Palmyra, standing at the crossroads of several civilizations, is a symbol of the complexity and wealth of the Syrian identity and history," the director general of UNESCO, Irina Bokova, said in a recent statement, adding that extremists were seeking to "destroy this diversity and richness."

Hatra

The Iraqi fortress city of Hatra is believed to date back to the Parthian empire in the 3rd or 2nd century B.C., and it later became the capital of the first Arab Kingdom. The city, known for its huge walls, flourished during the Mesopotamian era and bears the influence of both the Roman and Persian empires. Video released in March by the Islamic State showed the group using sledgehammers and even guns to destroy carvings and statues.

"Praise to God, who enabled us and the soldiers of Islamic State to remove the signs of polytheism," one militant says in the video. The destruction in Hatra came just a few days after attempts by the Islamic State to bulldoze ruins at the Assyrian city of Nimrud, a site currently on the tentative list to become a world heritage site.

Ashur (Qal'at Sherqat)

Ashur, also known as Assur, is a city in modern-day Iraq that dates back to the third millennium, and it later became the first capital of the Assyrian Empire. The city was associated with the god Ashur and became an important religious city.

Ashur was first declared in danger by UNESCO in 2003 due to the planned construction of a dam that would have flooded its ruins. Due to the city's proximity to Islamic State-controlled territory, there have been fears that it could face destruction or vandalism. In May, there were a number of reports that the city's ancient arches had been blown up by militants.

The ancient city of Aleppo

Located at an important point along trading routes since the 2nd millennium B.C., Aleppo has had a rich history and has the architectural legacy of a variety of different empires, religions and time periods. The city has various buildings of historical importance, including its famous citadel, a large fortified palace that dates back thousands of years.

Unlike some other sites on this list, Aleppo remains an inhabited and major city, and since the Syrian war began in 2012 it has been divided between rebel forces and government troops. The city became a target for the Islamic State during the summer. A number of important sites in the city have been damaged during the fighting — for example, the famous minaret at the 11th century A.D. Great Mosque of Aleppo was destroyed in 2013.

The ancient villages of Northern Syria

These villages, also known as the "Dead Cities," are located in the northwest of the country and date back to between the 1st and 7th centuries, but they were all abandoned by the 10th century. Their ruins present a picture of life in the Antiquity period and the Byzantine period, but the civil war in Syria has posed a threat to their preservation, with refugees and fighters taking refuge in the ruins at points.

Samarra archaeological city

The archaeological city of Samarra in Iraq, once the capital of the Abbasid Caliphate, is considered an especially important historical site by UNESCO as it is the "only surviving Islamic capital that retains its original plan, architecture and arts, such as mosaics and carvings." The city is well-preserved as it was abandoned relatively early, and only 20 percent of it has been excavated so far.

The modern city of Samarra became a notable source of tension between Sunnis and Shiites after the Iraq war. Last year, the city was overrun by Islamic State fighters, who came close to a major Shiite shrine in the city, though they were then pushed back by airstrikes ordered by the Iraqi government.

The Crusader castles

Crac des Chevaliers and Qal'at Salah El-Din are two castles in Syria that date to the period of the Crusades and represent an important mixture of European and Near Eastern influences. However, both have been the scene of heavy fighting: In 2013, rebels said they had just managed to defeat regime troops fighting in the walls of the Crac des Chevaliers, though the Syrian army retook the castle in 2014.

Ancient city of Damascus

Damascus is the capital of Syria and one of the oldest continually inhabited cities in the world, with some excavations showing the city was inhabited as early as 8,000 to 10,000 B.C. The city became the capital of the Umayyad Caliphate and has been important to Arab culture since. Within the walls of the Old City, UNESCO says there are 125 protected monuments, including the Umayyad mosque, still one of the largest mosques in the world.

There had been concerns about the Old City of Damascus due to a population decrease, in which residents moved out of older buildings to newer housing, leading to some abandoned areas. Fighting in the Syrian capital has also caused serious concern. When rebels entered the Old City in 2012, the government shelled it.

Ancient city of Bosra

Bosra was once the capital of the Roman province of Arabia and still features a 2nd-century Roman theater within the Old City walls. It contains a number of monuments from the Nabataean, Byzantine and Umayyad periods, too.

The city, however, has been the site of considerable fighting during the Syrian civil war, putting much of the Old City at risk. There have been reports of shelling and bombing in the city, and online videos have appeared to show snipers shooting from the theater. Relics from the site have been looted since at least 2012.