Satellite imagery shows that at least 290 cultural heritage sites in Syria have been damaged by the country's civil war, a UN agency has said.
Syria is home to archaeological treasures that span thousands of years of written history, from the Roman ruins in the desert oasis of Palmyra to the towering Crusader castle known as the Crac des Chevaliers near the Mediterranean coast.
The nation's capital, Damascus, is one of the oldest continually inhabited cities in the world.
It has long been known that Syria's archaeological sites have been looted and its historic buildings damaged since the country's conflict began in March 2011, but the new report by the United Nations Institute for Training and Research (Unitar) provides one of the most substantial looks yet at the scope of the problem.
Analysing 18 cultural areas using commercially available satellite imagery, Unitar determined that 24 sites were totally destroyed. Another 104 sites were severely damaged, 85 moderately damaged and 77 possibly damaged, the report said.
The evidence provides "alarming testimony of the ongoing damage that is happening to Syria's vast cultural heritage", Unitar said. "National and international efforts for the protection of these areas need to be scaled up in order to save as much as possible of this important heritage to human-kind."
Unesco World Heritage sites in Aleppo, Damascus, Palmyra and the Crac des Chevaliers have all sustained major damage, according to Unitar.
Sites across the country have been exposed to different threats. In some places, shelling and other military activity are responsible for the destruction, while in other places illegal excavations and civilian construction are to blame.
The report offers before and after photographs from several sites that indicate the scale of the loss.
Photos of Aleppo show grey craters and mounds of rubble around the city's famed citadel where historic buildings, including the Carlton hotel, used to be. Heavy damage is also evident to the Umayyad Mosque, which has lost its 11th-century minaret.
Images from the ancient city of Dura-Europos and Palmyra show extensive looting, with the ground peppered with holes from unauthorised digging.