Blue

I wrote that Cardigan Castle ceased to function as a military asset after it was deliberately disabled during the Civil War. Well yes, but... There is a WWII pill-box, built from concrete by the Home Guard, within the castle walls, positioned to provide a view of (and firing position for) the bridge over the river Teifi. There was a genuine anxiety in those years that Britain might be invaded from the west, via Ireland. Geography and military necessity produce the same solution eight centuries apart

Today we fell upon an even more extreme example of the same phenomenon. A steep-sided hill, 156 metres high, overlooking two bays - one a natural harbour - with a long, low promentary between them. An earthen wall and ditch around the flat summit, along with some deliberate steepening of the slope, made a highly defensible position

Archaeological digs have found a post-hole from the Bronze Age (around 3000 years ago), round stones - quite possibly sling shot - from the Iron Age (a few centuries later), and remains of a roundhouse and storage barn from the Roman period (at least 1600 years ago). Like the castle, the hill has its modern reincarnation: it is now topped by a missile teacking station!

The history was a serendipitous find. We were there to soak up the sea and the light on what has been the most exquisite day of our visit: low temperature (4C when we set off) coupled with still air, calm sea and bright sun that still feels warm, even in the last days of November. I took many, many pictures, some with rich, bright colours, ponies silhouetted against the sea, a flight of swans crossing the tiny island in this picture. In the end I've picked this because it best captures the dazzling, shocking, mesmerising, constantly shifting wall of blues that assailed us as we made our way along the cliffs - slow progress when you cannot help but stop to take it all in every few moments