Carew Castle, the Tidal Mill and the Millpond

Carew has an unusual concentration of good things in a very small area, and a flat three-mile path links all of them.

The circuit runs round the millpond, a 23-acre sheet of water created by damming the tidal Carew River. Start from the castle car park and follow the waymarked route — it's well signed, largely level, and the surface is grass and packed earth rather than tarmac, so it's a boots-or-wellies walk in winter and fine in trainers in summer.

Carew Castle dominates the first stretch. It's an odd and interesting building because it was never finished as one thing: a Norman castle rebuilt as a fortress, then partly converted into an Elizabethan mansion with big mullioned windows punched through the defensive walls, and then abandoned after the Civil War. The north range in particular reads as a Tudor country house with a castle behind it. It's leased to the National Park and open to visitors in season.

At the far end of the dam stands the Carew tidal mill, sometimes called the French Mill. It's a four-storey stone building of the early 19th century and it's the only restored tidal mill in Wales. The mechanism is simple and clever: the incoming tide fills the pond through sluices, the gates close at high water, and the trapped water is released through the wheels as the tide falls, giving two grinding periods a day dictated entirely by the moon. It worked commercially until 1937. The machinery is still in place inside.

The rest of the loop takes you round the quieter western and northern shores, through fields and a bit of woodland, with the castle in view for most of it. The pond is good for birds — herons, little egrets, kingfishers, wintering wildfowl — and the margins are thick with dragonflies in summer.

Don't leave without walking to the road junction to see the Carew Cross. It's a wheel-headed Celtic cross over four metres high, carved in the 11th century as a memorial to Maredudd ap Edwin, a king of Deheubarth who died in 1035. It stands at the roadside, free to look at, and it is one of the finest early medieval monuments in Wales.

Where to eat. There's a pub at the crossroads opposite the cross and a tearoom at the castle in season.

With children. This is a good one: short, flat, waymarked, with a castle and a mill to break it up, and a decent chance of seeing a heron.