Add defense bonus to city ruins

Is there anyway to add a defensive bonus to city ruins?

Not that I know of. It would be cool, though.

You cant. But if you have C3C you can do another thing on custom maps. If you have a ruin of lets say Pompeii then you can use the LM Terrain to make one square called "Pompeii" and place a ruin on it. Then you can modify the Pompeii terrains defence bonus.