Ancient Syrian castles serve again as fighting positions But today, in the third year of a bloody civil war that has killed more than 70,000 Syrians, the hulking citadel has resumed its strategic role of earlier eras. President Bashar al-Assad's forces have taken position in it to shell their enemies, and Syrian opposition fighters say they are desperate to capture it. For both sides, what was true in war then is true now: Those who control the citadel have the power to alter the front lines. Modern Syria is dotted with medieval castles and citadels, many built high upon the ruins of earlier Roman or Mesopotamian dynasties in an archaeological landscape that experts say is among the richest in the world. But as the fortified structures gain new strategic purpose in Syria's devastatingly modern civil war, archaeologists worry that what withstood ancient armies and earthquakes may now fall victim to airstrikes, shelling and other forms of 21st-century warfare. Because of limited access, archaeologists and other experts say it is close to impossible to confirm reports of damage and looting to Syria's castles and citadels, including the famed crusader castle Crak des Chevaliers, whose south wall has been nearly destroyed in the fighting, according to Syrian rebels. But it is certain that they and many other historical and archaeological sites "have been affected by violent fights or occupation by armed forces for military purposes," said Veronique Dauge, chief of the Arab States Unit at the UNESCO World Heritage Centre. Both the rebels and the Syrian government have pledged publicly to protect the nation's ancient structures. But they are intensely battling for their control. In Aleppo, the citadel has proved critical over months of fierce fighting. Syrian opposition fighters say regime snipers have staked out positions in the arrow slits of the ancient fortress, rendering the hilltop impregnable and allowing the snipers to cement a front line that roughly dissects the city in half - one swathe controlled by rebels, the other by the state. Near the city of Homs, in the strategic Orontes River valley, which has served as a battleground of clashing empires for more than 4,000 years, Syrian rebels say they only recently routed regime troops from the heavily fortified walls of Crak des Chevaliers - one of the Middle East's most fantastic crusader castles. In the center of the old city of Homs, the citadel has changed hands at least three times in recent months, although some fighters say they only managed to hold it for a day. There, opposition forces say the regime has used the fortress to maintain its stranglehold on one of Syria's most important and most virulently anti-Assad cities.