Acropolis, the most crucial construction of the whole city, sits at the heart of the city, also controls the politics, economics, trades and the millitary from the highest peak of city. Upgrading the Acropolis allows you to unlock brand new buildings, to upgrade other buildings to a higher level, to launch more marches of larger sizes, to contain more troops, and also to receive more League Assistances. In the Acropolis, you have an overview of city economics, troops, buidlings, which assists you manage the functioning condition of the city better.