Your Hall is the Center of your city, and all neighbors who visit you city will (as best as possible) enter your city with your Hall in the center of their opening screen. The Hall may be moved, but never destroyed.

Camels randomly appear in front of the Hall the first time each Day that you visit a neighbor.

Research unlocks new levels to the Hall that will add a bonus to tax collection:

Townhall City Hall Royal Hall
Code of Laws Tax Code Civic Service
5% 10% 15%