Pembrokeshire, Wales
The Castle, Haverfordwest SA61 2EF
The inner ward of the castle stands free to explore in the middle of Haverfordwest, with a town museum built into part of the site telling the wider story. It's a modest survival rather than a grand one, but its position right in the town centre makes it an easy stop.
The town museum built into the castle grounds, which fills in the history the bare walls don't tell on their own.
The inner ward is free and open daily, so it's worth combining with a wider look around Haverfordwest rather than treating it as a standalone trip.
Inner ward free daily; town museum adjacent