As soon as Hitler's forces occupied the Channel Islands he ordered a series of fortifications to defend the only British territory he ever conquered.
The problem was he never stopped, pouring men, concrete and weapons into the Islands until his officers began to refer to his "inselwahn" his island madness and the Channel Islands had become the most fortified place - on earth.
By 1944 the Channel Islands had taken in over 8% of the concrete destined for the Atlantic Wall and had more guns than 600 miles of Normandy Coast. Of the German commanders only Rommel understood the implications for the invasion they all knew was coming.
