Stronghold

The stronghold is the backbone of the city which needs to be leveled up in order to level up other buildings. In addition to the listed pre-requisites, the wall always has to be the same level as the stronghold before the stronghold can be upgraded.

In addition to being leveled up, the stronghold also gives you an overall view of your city, where you can see production of each of your resources, your total number of troops, total marches, etc.