Aleppo's ancient Umayyad mosque, whose minaret was destroyed in fighting on Wednesday, offers a chilling window into the intractability of Syria's civil war, now in its third year.
The iconic mosque in Aleppo's labyrinthine Old City has been a key battleground since last July, with rebels seeking the ouster of Bashar al-Assad's regime laying siege twice but each time managing only to keep control for less than 48 hours.
Rebels overran the mosque for the third time in late February and have since managed to hold sway through weeks of erratic shelling and "guerrilla" sniper attacks.
Its minaret was blown up on Wednesday, with state media blaming "terrorists" and the rebels saying the army was responsible.
An archaeological treasure in the UNESCO-listed Old City, the Umayyad mosque was originally built in the 8th century but was apparently destroyed and then rebuilt in the 13th century.
Despite controlling it, the Free Syrian Army (FSA) rebels acknowledge their grip on the mosque remains shaky until they seize the nearby regime-held Citadel -- a mediaeval fortress overlooking the site.
The Citadel, a fine military vantage point for tactical shelling and sniper fire, has stubbornly remained elusive and the rebels are able only to maintain an uneasy stalemate with no tangible sign of a way forward.
"Neither side (is) able to establish a monopoly of force across the entire country," said Elizabeth O'Bagy, a Syria expert at the Washington-based Institute for the Study of War (ISW).
"The battle lines in Syria continue to ebb and flow with both the rebels and the regime taking territory in some areas and losing territory in others," she told AFP.
Syria has paid a heavy price for the brutal impasse, with the war leaving more than 70,000 people dead, millions displaced and countless cities and neighbourhoods ravaged.
But at the mosque, rebels wielding home-made grenades, guns and bandoliers of bullets have remained defiant in the face of near-daily shelling since taking control of the site.
One group warming their hands by a smouldering bonfire stood up at routine intervals, especially after every new round of shelling, to bellow "Allahu akbar" (God is greatest!) in unison -- to signal to regime soldiers that they remain undefeated.
The fighters tread a delicate tightrope between holding control over the mosque and not damaging it, FSA fighter Abu Omar said, fingering his prayer beads.
But even before the minaret's destruction on Wednesday, the mosque had suffered extensive damage anyway. Its bullet-pocked and soot-stained walls bear the physical scars of a messy war.
Antique furnishings and intricately sculpted colonnades have been charred, valuable Islamic relics ransacked, and ancient artefacts -- including a box purported to contain a strand of the Prophet Mohammed's hair -- looted.
The place was once filled with worshippers who prayed on green and gold velvet carpets. Rebels, sandbag bunkers and rolls of barbed wire now surround it like a garrison.
But the rebels have managed to salvage ancient handwritten Koranic manuscripts and have hidden them in a "safe place", lest the mosque slip out of their control again.
"They (regime soldiers) can watch everything from the Citadel," said Abu Omar, revealing a picture of himself on his cellphone posing with the retrieved scriptures. "We don't want it to fall back into the wrong hands."
The first two times the mosque was lost, he said, a regime sniper planted on the minaret caused much grief. They could not reach the minaret because of non-stop shelling, but were able to take him down in their third attempt.
And another gambit paid off. The rebels gave up access to two adjacent cobblestoned streets leading to the mosque and then cornered regime forces from behind. "That trick was a blessing from Allah," Abu Omar said.
Rebel snipers now patrol all the access points from which the army may try to retake the site around the clock, he added.
Chilling AFP video from last year shows how dramatically the army retook the mosque from the rebels, overwhelming them with explosives by shelling and bombing their way in.
And such raids in the future by troops launching assaults from the Citadel cannot be ruled out. An Islamic landmark with Greek, Roman and Byzantine ruins, the Citadel has been an icon of Arab military might for centuries.
Its deep moat, connected to a number of underground passageways and caves, and other defence mechanisms continue to be as decisive now as they were hundreds of years ago.
Moreover, the regime military is equipped with superior heavy artillery, mortars, tanks, helicopters and night vision equipment.
"The rebels have shown an ability to target key centres of the regime, but have faced difficulties in holding territory. The regime has the ability to go on the offensive and retains military superiority," the ISW's O'Bagy said.
"The only way that this type of stalemated fighting may shift is if there were to be significant support given to the opposition to shift the balance of power in their favour. Otherwise, there is going to be a long war of attrition ahead."