By Patrick Jackson
BBC News Online
The sight of tanks prowling along a cemetery's paths and gunmen crouching behind tombstones would be alarming in any circumstances, but it has a special resonance in Iraq's great burial ground at Najaf.
Perhaps only satellite photos can convey the cemetery's sheer size
This vast tract of domes and humbler tombs is on a site which Imam Ali, one of Shia Islam's most revered figures, is said to have decreed to be the entry to Paradise itself.
For centuries, Muslims from across the Shia world have sought to be buried here, within sight of the city's gilded Imam Ali Shrine.
Known as the Valley of Peace, it is said to be one of the largest graveyards on the planet, if not the largest.
If Najaf itself is one of Iraq's biggest cities, with a population of nearly 600,000, then the adjoining city of the dead holds the remains of millions, stretching for up to 10km (6 miles) along the valley.
Since the eruption of anti-occupation violence among the followers of radical cleric Moqtada Sadr in April, heavily-armed fighters from his Mehdi Army militia have periodically appeared in the cemetery - for the cameras at least.
The sprawling avenues of tombs and crypts make ideal cover
"We ambush their patrols and the Americans cannot get into the area, because it's full of winding lanes and underground mausoleums," gunman Abdul Zahra Hadi told Reuters news agency from inside the cemetery.
"We can hit and run and hide inside the many tombs."
The Valley of Peace has a much longer history as a place of shelter: crypts among the estimated five million graves once harboured fugitives from Saddam Hussein's security forces.
Despite dating back to the 7th Century, the cemetery is still functioning.
Before the fighting erupted, it was witnessing dozens of burials each day.
Some of those buried in Najaf most recently were victims of Saddam's secret executions, recovered by their families from anonymous mass graves to be moved, at the last, to the Valley of Peace.