Atlantic Wall
Early in 1944, Field Marshal Erwin Rommel was assigned to improve the Wall's defences.  Rommel believed the existing coastal fortifications were entirely inadequate and he began strengthening them.  He knew that the beaches between were barely defended, and the Allies could land there and capture the ports from the land.  Under his direction, a string of reinforced concrete pillboxes were built along the beaches, or sometimes slightly inland, to house machine guns, anti-tank guns, and light artillery.  Mines and antitank obstacles were planted on the beaches themselves, and underwater obstacles and mines were placed in waters just off shore.  The intent was to destroy the Allied landing craft before they could unload.