As you round the corner at the lower end of the high street, hugging the fenced boundary of the school field on your left, the coast road opens up before you. It's a mile of simple, unlit road that runs east/west with one lane in each direction, and it's as straight as an arrow. This is the back straight of our weekly three-mile run. The pavement we're on is a two-metre wide belt of grey square slabs, set back from the curbside by a three-metre strip of grass that runs the whole mile. Except for the daisies and the occasional dandelion, there are remarkably few weeds. Across the road, over to our right, the pavement sits flush against the curbside, and along its far side is a flat, grassy headland roughly fifty feet wide. Beyond that lies a network of paths that crisscross the steep dunes flanking the beach some fifty feet below. From our vantage point, we can see a thin strip of sea, way off in the distance, poking above the headland before it quickly meets the horizon to...