Public Order question

[gran_guitarra]

I know the best way to induce public order is to get buildings that counter the negative effects of things. So Public Health for squalor, etc.

My questions are:
What causes unrest and how do I get rid of it? I know spies do this, but I doubt that there are spies in every single one of my cities, which have spies to counter-spy for me.
What is culture penalty, and what causes it? Furthermore, how do I counteract its effects?

[MarcusAureliusAntoninus]

Unrest is caused by spies, just happens in newly conquered cities and slowly goes away, and sometimes unrest is just a perminent staple in a particular city.

Culturaly penalty is caused from owning a city of a different culture. You can get rid of it by tearing down or building over (upgrading) buildings in the town that were built by the previous owners. Upgrading the town a level will get rid of most of the culture penalty. Temples also seem to effect it more than other buildings.

[Hegix]

Do town level buildings, farms, granaries, walls and all other non-destroyable buildings add to culture penalty too? Carthage, for example, comes with a pre-built lvl 5 level building. Theres no way to get rid of it.

[Underhand]

Do town level buildings, farms, granaries, walls and all other non-destroyable buildings add to culture penalty too? Carthage, for example, comes with a pre-built lvl 5 level building. Theres no way to get rid of it.
Carthage starts with that? Damn, I thought I'd just been a bit slow (despite taking the city in the first fifteen years or so). The 'city level' buildings have a major impact on the culture penalty, so you're forever stuck with a 30% or so penalty if you capture a huge city. I don't know about the other non-destroyable buildings, but I think it likely that they have an effect.