Pembroke Castle and the Mill Pond

Pembroke is built on a limestone ridge with water on both sides, which is why the Normans put a castle on the end of it. The Mill Pond walk goes round that water, and it is the best hour you can spend in the town.

Start at the castle. Pembroke Castle is a genuinely major piece of medieval architecture — the great round keep is nearly 25 metres tall with walls several metres thick at the base, and it was never taken by the Welsh. Beneath it is the Wogan Cavern, a large natural limestone cave opening onto the river, used since prehistory and later fortified as a castle boat store; it's an unusual thing to have under a keep. Henry Tudor was born in the castle in 1457 and left Wales as an exile at fourteen; he came back in 1485, landed at Mill Bay on the Dale peninsula and became Henry VII a fortnight later.

The walk itself follows the northern shore of the pond, which is a tidal river dammed in the medieval period to power a mill. It's now a still sheet of water with reedbeds at the top end, and it's good for birds: herons stand about all year, kingfishers are regular, and there are cormorants, little grebes and, at the quiet end in the evening, otters.

Cross at the top of the pond and come back along the far side, which is where you get the view everyone photographs — the whole castle rising straight out of the water with nothing in front of it. Look across to Monkton Priory on the other ridge, a Benedictine foundation of the 1090s with a long, striking church still in use.

Come back into town along Main Street, which is essentially one continuous medieval street with the castle at one end and the remains of the town walls and Barnard's Tower at the other. There are stretches of wall still standing behind the buildings on the northern side.

Where to eat. There are pubs and cafés along Main Street within a few minutes of the castle gate.

With children and buggies. Most of it is fine, but there are steps and unmade sections, so it isn't a fully step-free loop. If you want guaranteed level ground, do the stretch nearest the castle and turn back.

Combining it. Carew Castle and the tidal mill are ten minutes away by car and make a good pairing — see the Carew circular.