Porto Franco is a fictional Iberian city set during the early Age of Exploration, playable in Maritime Kingdom. The player builds the city as they progress. It is noted for it's tropical, yet sometimes arctic climate, sporting ice-covered palm trees and other Obstacles. It originally had a Castle, Dock, and Merchant's Guild, all in ruins, and a number of other Special Buildings surrounded by the overgrown jungle.
The city was established but then abandoned for many years. The player and members of the ruling class of The Kingdom resettled here after escaping a revolution, which had resulted in the fall of the capital and the capture of The King. The player is tasked with rebuilding the ruined city while pursuing The Crown Jewels in order to retake the capital and rescue the King.