The coastline between Conil de la Frontera and Cape Trafalgar, Spain, is something I am quite familiar with. The lighthouse at the Cape is visible from the house we stay at in at Fuente Del Gallo, and beyond that, on a clear day, you can see Morocco. Swinging round to the right, looking out to sea, is where the Battle of Trafalgar took place. 200 years ago, the top of the cliffs may have given a grandstand view to any spectator.
I have planned the walk to the lighthouse many times, but it was only recently that I tried to do it. Only 14 km, it needs a cool day and a low tide if you want to do it entirely on the beach, just to clear the headlands.
About halfway is El Palmar, where some of the beach and dunes form a nature reserve. There have been plans to build a huge hotel complex here, which seems a bit mad. There is a campaign to stop this development, and a petition with 100,00 signatures. See The Green Guide to Spain or www.salvarelpalmar.es for more details. Some photos en route: