bare estuary exposed forest green hills landscape low Mawddach mudflats natural nature peaceful river seashells tide tranquil view wales water welsh architecture cascade dam fall fresh Great Britain historical old oxygenated oxygenation power stone strength strong tunnel turbine wall ancient carved church elements eroded erosion expression king noble portrait religion religious sad serious worn blue bluebells campion coastline flowers island Pembrokeshire pink plants rock sea spring channel chute cloud lake overflow race reservoir sky Barmouth bridge gantry girders mountains railway resort sandbanks shadow shore tidal clouds planks rails route travel wooden coastal flora maritima Silene uniflora Skomer united kingdom white wild countryside direction farm gate hedge house lane Powys quiet road rural transport tree verge winter algae beach coast pool sand seaweed