The greatest buildings you’ll never see: 20 monuments lost in conflict

Once the largest mosques in the world, built in the 9th century on the Tigris River north of Baghdad. The mosque is famous for the Malwiya Tower, a 52-meter minaret with spiraling ramps for worshipers to climb. The site was bombed in 2005, in an insurgent attack on a NATO position, destroying the top of the minaret and surrounding walls.
Video: ISIS targets historical artifacts

An "oasis in the Syrian desert" according to UNESCO, this Aramaic city has stood since the second millennium BC and featured some of the most advanced architecture of the period. The site subsequently evolved through Greco-Roman and Persian periods, providing unique historic insight into those cultures. ISIS now controls the ancient city and has destroyed shrines, temples and monuments.

The most spectacular legacy of Buddhism in the war-torn country, among the tallest standing Buddhas in the world -- the larger at 53 meters, the other 35 -- had survived over 1,500 years since being carved out of sandstone. The Taliban considered the monuments idolatrous and destroyed them with dynamite.

Yemen's capital city of Sanaa has seen several suicide bombings for which ISIS claimed responsibility, and air strikes by the Saudi-led coalition -- although it is unclear who is responsible to the latest damage. These have affected both the old fortified city -- inscribed on UNESCO's World Heritage List since 1986 -- and the archaeological site of the pre-Islamic walled city of Baraqish, causing "severe damage," according to UNESCO itself.

Continually inhabited for 2,500 years, and became the capital of the Romans' Arabian empire. The centerpiece is a magnificent Roman theater dating back to the second century that survived intact until the current conflict. Archaeologists have revealed the site is now severely damaged from mortar shelling.

A world heritage site originally built in 715 by the Umayyad dynasty, ranking it among the oldest mosques in the world. The epic structure evolved through successive eras, gaining its famous minaret in the late 11th century. This was reduced to rubble in the Syrian civil war in 2013, along with serious damage to the walls and courtyard, which historians have described as the worst ever damage to Syrian heritage.

These 20-meter wide water wheels were first documented in the 5th century, representing an ingenious early irrigation system. Seventeen of the wooden norias (a machine for lifting water into an aqueduct) survived to present day and became Hama's primary tourist attraction, noted for their groaning sounds as they turned. Heritage experts documented several wheels being burned by fighters in 2014.

The fortress spans at least four millennia, from the days of Alexander the Great, through Roman, Mongol, and Ottoman rule. The site has barely changed since the 16th century and is one of Syria's most popular World Heritage sites. The citadel has been used as an army base in recent fighting and several of its historic buildings have been destroyed.

The covered markets in the Old City are a famous trade center for the region's finest produce, with dedicated sub-souks for fabrics, food, or accessories. The tunnels became the scene of fierce fighting and many of the oldest are now damaged beyond recognition, which Unesco has described as a tragedy.

This French-built suspension bridge was a popular pedestrian crossing and vantage point for its views of the Euphrates River. It became a key supply line in a battle for the city, and collapsed under shelling. Deir Ez-zor's Siyasiyeh Bridge was also destroyed.

The ancient Assyrian city around Nineveh Province, Iraq was home to countless treasures of the empire, including statues, monuments and jewels. Following the 2003 invasion the site has been devastated by looting, with many of the stolen pieces finding homes in museums abroad.

The Crusader castle from the 11th century survived centuries of battles and natural disasters, becoming a World Heritage site in 2006 along with the adjacent castle of Qal'at Salah El-Din. The walls were severely damaged by regime airstrikes and artillery in 2013, and rebels took positions within it.

The purported resting place of biblical prophet Jonah, along with a tooth believed to be from the whale that consumed him. The site dated to the 8th century BC, and was of great importance to Christian and Muslim faiths. It was entirely blown up by ISIS militants in 2014 as part of their campaign against perceived apostasy.

Among Syria's most famous Ottoman-style mosques, which also shows Mamluk influence through its light and dark contrasts. The vast site became a hub of the battle for Homs, itself a front-line of the conflict. The sacred mausoleum has been completely destroyed, and much of the interiors burned.

Memorial site to the 1.5 million killed between 1915 and 1923, the Deir Ez-zor became a yearly destination for pilgrims from around the world. The site included a church, museum, and fire that burned continuously. The complex was destroyed by ISIS in 2014.

A key city for the Greeks and Romans, established in 630 BC. Famed as the basis for enduring myths and legends, such as that of the huntress heroine of the same name and bride of Apollo. The ruins were some of the best preserved from that period, but in the wake of Libya's revolution, vast tracts have been bulldozed including its unique necropolis complex.

Home to one of the world's most impressive collections, with over 100,000 pieces that cover the entirety of Islamic history. The Cairo site was first built in 1881, the museum recently underwent an eight-year multi-million dollar renovation. Shortly after re-opening, a car bomb targeting a nearby police building caused catastrophic damage and forced the museum to close again.

This 121-year-old wooden building, humble but elegant, was home to the nation's first governor general Muhammed Ali Jinnah for the last phase of his life. The residency was attacked with rocket fire by a separatist group in 2013, and almost completely demolished. A new structure is being built on the site.

A 15-year civil war of incredible brutality, successive battles with Israel, and sweeping urban development has robbed the 'Paris of the Middle East' of much of its visual lustre. Once known for its landscape of swaggering Ottoman, French and Art Deco architecture, officials say just 400 of 1200 protected historic buildings remain.

Before-and-after photographs of the destruction. The US and ISIS trade blame for its loss.