For prison only themes, I've always been a fan of the Panopticon.
I like the idea of the Panopticon, but that always feels like a far more sci-fi or at least somewhat futurist concept, not necessarily something that would show up in high fantasy or gothic horror.
That being said, in my brain, White Wolf already laid claim to that one when they made it one of the branches of the Technocracy, as an outgrowth of the New World Order. My OCD always tends to steer me clear of fancy terms if they've been used for something in another system I'm familiar with.
What's so fancy about it? Obsidian Glass crater in sand a half Mile high all around. Panopticon in the center observing all. ---