Fog of War

The Fog of War surrounds all areas where there are no units or buildings that have a line-of-sight in order to see what's happening in that zone. These areas become dark and the last known objects and buildings are still visible but no units are visible. Also, any changes (eg: a building gets destroyed, new buildings are cosntructed or a resource is depleted) will not be shown in the Fog of War area, requiring the player to send some units in order to get updates.