So this is something i really miss from civ 4 that was never implemented again, its the ability for like a civ who has a 'colony' meaning a city on another continent that becomes unhappy and can rebel and form a new civ so in this game like a new culture. So in a way a american revolution can occur but not neccessarily 'american'. Just a suggestion would be intrerested to hear what others think.

Just wanted to say Really looking forward to this game, i am a disallusioned long time civ fan so this was a relief to see some new innovation and by amplitude so i am undoubtadley on board.

There's a stability factor implemented in the game for managing your cities/territories, which will act as a happiness factor. From what I understand of the gameplay footages revealed so far (please correct me if I'm wrong), at the city level, you'll be able to increase stability by using an administrator. At your empire level, you'll be able to increase stability from Civics and Wonders (and Fame as well maybe ?). If you haven't seen it yet, you should definitely check the walkthrough from GUD, which is explaining the stability factor.

Now, from what I've read and understood, the less stable your city/territory is, the more likely a revolution will occur, generating independant units/armies. I'm not sure (again, correct me if I'm wrong) that those "independant" units/territories will turn into a new culture though.

Finally, cultural influence from other civs will also play a big role on stability.