Capitol Building

The Capitol Building goes in your capital, and its level plus one is the number of cities you are allowed, so building it at all gets you your second city. No other city is offered one.

Research caps that at 2 cities until you research Civics at a Research Institute. Administration and Provincial Government raise the cap, and Imperial Charter removes it.

Your first city is your capital. You can move that to another city by upgrading its Statehouse into a Capitol Building.

Being the capital is worth 10 people on its own, whatever is built there.

Build one in your capital and then open it. It lists every city you hold with the people and the resources in each, adds them up, and says how many cities you are allowed against how many you have.

Capitol Building costs 1,200 wood and takes 40 minutes to build.

You need a Town Hall at level 4.

Every level after that costs about 80% more than the one below it, and takes on one more resource: stone at level 2, coffee at level 3, glass at level 4, mana at level 5. Every level then wants more of each. Growing your empire is meant to be slow.