Buildings are a key component to success in Tribalwars 2 and also display the advancement of you as a player in the game. Each building has a point value, and the sum of all building points is displayed over your city in the map overview. The Headquarters is tied in directly to your building options, as the Headquarters level determines which buildings you may build.
In the example below the Heaquarters requirements for the Wall have been met. The Hospital is still locked as the Headquarters is below level 6
Building requirements are tied to 5