When I parked on the side of the road, just north of the town of Llithfaen, I could hardly see 3 metres ahead. The highway curved away in front and behind, disappearing into thick mist. To the side, the land dropped down abruptly, a wall of solid gray. I could just make out a trail marker, pointing steeply up a bracken covered hillside. I laced up my boots and headed into the mist. A stone wall ran straight up the hillside before disappearing into the cloud a short distance a