By Crispin Thorold
BBC News, Byblos
Unesco has launched an urgent appeal for funds to restore world heritage sites following the recent conflict between Israel and Hezbollah.
Byblos is an ancient port city that is in urgent need of a clean-up
The UN's cultural organisation says the worst damage was in the northern port of Byblos, where a thick layer of oil coated ancient and medieval remains.
The damage was caused by the Israeli bombing of a coastal power station.
Ruins in Baalbek and Tyre were damaged by vibration from nearby explosions and need restoration.
Baalbek has some of the finest examples of imperial Roman architecture outsie Italy.
"Although it was not directly hit and did not suffer any major visible damage, cracks in the stone were probably widened by the shaking caused by nearby bombings," said Mounir Bouchenaki who led the UN mission that reported on the findings.
Further investigations were needed to ascertain the extent to which Baalbek's colossal structures were damaged, Mr Bouchenaki said.
Byblos, which has been continuously inhabited for more than 7,000 years, is still suffering from the oilslick.
This is causing dismay among local people and archaeologists around the world.
The Lebanese authorities have not been able to clear up the oil, which leaked when the power station at Jiyyeh south of Beirut was bombed by the Israelis.
As the wave reaches the shore in Byblos, more oil is brought in from the Mediterranean Sea.
This is a town that has been invaded by many civilizations - but a man-made environmental disaster now threatens the port.
The remains of the Roman quarries on the shore's edge glisten in the sunlight.
They have been blackened by the oil, as has the base of the tower the Crusaders built here.
Baalbeks monuments could have been affected by heavy bombing nearby
Unesco says that urgent action is needed to protect Byblos.
The Lebanese government and international groups have begun the clean-up, but it is a painstaking task.
"It will be very long because we have to take many volunteers to clean up all the stones," explains Philippe Messenc, who has been working with the French navy team.
"You have many porous stones, so you just have to brush the stones to clean up all the shoreline."
To clean the port's walls, the authorities first have to stop the slick.
Much of the Lebanese coast has oil on its beaches. The economic and environmental damage is extensive.
But in Byblos, the local people say they will not give up until their heritage is restored.
Volunteer worker Osama Qallab sums up the spirit of Byblos with the two words "dynamism and continuity".
"I have to count on these two words, because we want to stay here, we want to live here, we want to make the history - we want to be the actors, not only the spectator," he says.
Unesco has committed money and expertise to the restoration.
But it is the will of the local people that this ancient town now needs most.