During the German invasion threat in 1940 defences were built along many parts of the eastern coast of Britain to prevent a landing by sea and tanks from advancing.  Around East Lothian there are still many anti tank blocks visible including these which are beside Gosford Sands where woodland has obscured this “wall” of blocks.  Many blocks were made by soldiers and Polish servicemen and Prisoners of War.  Close by was the Gosford Camp where nearly 4000 POWs were imprisoned by the end of the war.  The prisoners were instructed to make these large concrete anti tank blocks here which stretch a long way in the woods with some having initials and dates in 1940.  About a kilometre away is the extra showing part of the sea wall which was built using some anti tank blocks as a base but much of the wall above has collapsed. 
While this is not a conventional wall in the normal sense it acted as a defensive wall so seemed appropriate for Bobsblip’s challenge today.