Signal Fires are small beacon-structures that can be found on many maps, either in Skirmish or War of the Ring mode. When a faction captures them by raising the flag, that player's powers will take less time to recharge after being used.
An uncaptured Signal Fire
In Skirmishes at Minas Tirith or Dol Guldur, the faction that is based within the fortress itself starts out with two Signal Fires already possessed.
Health-points: 1000