Lighthouse

Once a Longship Dock (or a Harbor for the Clan of the Raven) is built and  is obtained, the player can build a Lighthouse as an extension of the Dock and start trading Kröwns in exchange for   Commercial Influence through Greater Trade Routes. Each route gives as well some happiness bonus.

Building a lighthouse renders the dock its attached to, immune to Kraken event. Any additional docks are still vulnerable.