The wall where the cross once hung is pockmarked by bullets. Below, where the altar once stood, lies a pile of greasy engine casings and spare parts. Oil stains spot the floor of the church, which evidently had been turned into a garage and now stands empty and desolate like the rest of the town.

Next door, in a row of dimly lit stone chambers that once served as a monastery, metal bunks lie overturned amid piles of clothes, cooking utensils and various personal belongings. Palestine Liberation Organization posters and slogans cover the walls.

In another part of town, the large St. Elias Church is in similar disarray. The now-departed Palestinians had apparently found a new use for this church as well: the pews inside have long since been removed, and a volleyball net stretches across the interior between two pillars.

This is the Damour now being put on display by the Israeli Army, which captured the PLO-held town 12 miles south of Beirut at the start of its invasion of Lebanon last month after pounding it relentlessly from land, sea and air.

Formerly inhabited by about 30,000 Lebanese, almost all of them Christians, Damour was overrun by Palestinian guerrillas during the 1975-76 Lebanese civil war. Its inhabitants were driven out, and the town was turned into a Palestinian military stronghold dominating the coastal road from southern Lebanon into Beirut.

During a tour Friday organized by the Israeli Army press office, reporters were taken to see the churches that had been turned into Palestinian guerrilla installations, huge arms and ammunition depots in residential buildings and a handful of Christian families who have returned to their former homes. Access to the town is normally restricted at several Israeli checkpoints.

One large house, of which the Israeli guides did not seem to be aware, contained a stockpile of Soviet-made SA9 missiles and a PLO prison. The surface-to-air missiles, fired from mobile launchers, reportedly were delivered by Libya last year. A dank basement under the heavily damaged house was divided into small cells just large enough for a person to lie down.

The emphasis of the tour was on the Palestinians' sacrilege and desecration, but Damour was also the scene of awesome destruction and of fierce Israeli shelling and air strikes.

Where facades of deserted buildings have not been blasted away entirely, they are scored with more holes than a Swiss cheese. In a few places, all that is left of a building is a set of pillars, giving the appearance of historic ruins--the effect of centuries of wear instantly achieved.

One of the tour's escort officers, a large man with a small moustache and tufts of frizzy hair sticking out from under his Army hat, appeared confused when a cameraman presented him with a piece he had picked up from a cluster bomb, a deadly antipersonnel weapon sold by the United States to Israel on condition that it be used strictly for defensive purposes.

Palestinian forces originally overran Damour, formerly a stronghold of the Christian followers of ex-president Camille Chamoun, in reprisal for the destruction by rightist Christian militiamen of the Palestinian refugee camp of Karantina.

Both Damour and Karantina had been regarded as enemy islands in territory controlled by the opposing sides at the start of the Lebanese civil war: Damour was in a predominantly Moslem area and Karantina in mainly Christian East Beirut. Each place was the site of massacres and forced evacuations.

In Damour, the house of Chamoun was blown up, and the local office of the right-wing Christian Phalangist party--then a minor influence in the town--was destroyed.

Today, thanks to their Israeli allies, the Phalangists are in control. Having completely subjugated the Christian militia loyal to Chamoun during the past couple of years, the Phalangists now are making plans to rebuild the town and return its Christian inhabitants.

Symbolizing the new control is a checkpoint on the town's bomb-damaged main street manned by militiamen of the Phalangist-dominated "Lebanese Forces" led by Bashir Gemayel.

In one district on the outskirts of Damour, three Christian families once again occupy houses they were forced to leave when the Palestinians took over.

One of the returnees, Amira Abdel Noor, 19, said her family had come back a week ago after having lived in a suburb of Beirut for the last seven years.

"We feel happy about the Israelis, because we wanted to come back, damage or not," she said.

Apparently less content was Nellie Andraos, who said she had left for a year after the Palestinians invaded, then returned and stayed until a few weeks ago when the Israeli attack forced her again to leave briefly.

"That's my house over there, all fallen in," she said, pointing across the street to a heavily damaged building. "How am I supposed to stay there?" She said that Israeli air raids had caused the damage. A huge bomb crater is about 20 yards away from the relative's house in which she now stays.

Up the hill from the cluster of houses stands another church that had been taken over by Palestinian guerrillas. Inside, discarded helmets, ammunition boxes and uniforms lie scattered among the piles of rubble. A dome that once covered the church now contains gaping holes from Israeli bombs.

According to one of the Israeli guides, who gave his name only as "Mike," the church and nearby buildings were used as "advance posts" by the PLO to observe the road to Beirut. Holding an Israeli Uzi submachine gun that looked small in his large hands, Mike said that the bombing of Nelli Andraos' house, located near the PLO installations, could not be helped.

"Certainly Israeli Army intelligence is very good, but I don't think we know who is sitting in every house."

Apparently less explicable was the destruction of tin shantytowns on either side of the road to Beirut near the town of Khalde. The escort officer said that the demolished shanties had been run over by tanks, but he could not explain who had ordered the destruction or why.

According to a Lebanese resident, the shanties had been built by migrants under the aegis of the Syrian Army, which had been active in the area before the Israeli invasion. The presence of the shacks evidently was resented by longtime inhabitants who now live under the protection of the Israelis. One shanty that was still standing by the road to Beirut was burning as Christian militiamen stood by.