City
From Sons of Valhalla Official Wiki
The first building of any city is the Mead Hall. At it you can upgrade your fighting abilities and some of your equipment for Hack Silver and Gold Coins. You can also upgrade the mead hall to expand your city and get more building sites.
To the right of the Mead Hall is the Supply Warehouse, where you can restock your equipment.
At both ends of the city are gates, which block enemy access. Gates have 1000 HP and cannot be upgraded.
New buildings can be constructed at material piles.