If you watch Game of Thrones, then you know the Red Keep. It’s adjacent to the old town, but is a fort apart from it, and it protects the entrance to a protected little cove. It’s not a small fort, but it’s a lot smaller than the old town, and so they built it much higher. Thus, it allows a better lookout on to the Adriatic and over the old town as well. They film many scenes here because it’s not occupied, and I am sure setup and set management is much easier than within the old town.
I don’t usually post photos of myself, but Kate took a good one, and so here I am with at the top of the fort, with the adjacent old town and Adriatic behind me. Visit Dubrovnik, it is really a very rare place. But if you visit from April through October, be prepared for unbelievable crowds.