Puerto Rico, as I now know, was discovered by that Columbus chappy. He didn’t care for it so he left. Then the Spanish turned it into a colonial military base. Fighting periodically ensued amongst others such as the pesky English who wanted it, eventually the Americans got it, sort of. Well that is a very short and poor quality summary of Puerto Rican history. Anyway, Old San Juan was a walled city with some forts and the like. Visited one fort which was nice and is where I learned my history of Puerto Rico. This is part of the wall of which a fair bit remains and a watch post overlooking the sea.