I've read often enough of 'The race to the sea' where allies and Germans attempted to outflank each other until a continuous trench line ran from Switzerland to the French coast. Obviously the two sides would be unlikely to pop into Switzerland to outflank the other side, but what of the side on the French coast? Did the last few yards of trench get abandoned when the tide came in? Did the Navy get involved? I have only come across one mention, in a Biggles story where our intrepid airman comes to grief close to the seaward side and they manage to get round the end to safety. There are millions of photos of the Somme, Ypres, Verdun, etc. But nothing of the ends, does anyone know of any sources worth pursuing?