User blog comment:JAlbor/Assassin's Creed: Black Flag Q&A Opportunity/@comment-6517-20130816112629/@comment-6517-20130816185214

Makes you wonder why Havanna is depicted with a city wall then, unless of course it did, in reality, have one at the time.

There will be at least one invisible wall, otherwise there would be nothing to stop you sailing off to Africa, or exploring the Pacific by crossing the Yucatan.