German fortification of Guernsey reduce the number and quality of troops required to defend the western ocean areas. Whilst the Luftwaffe and Kriegsmarine had their roles in protecting the islands from the Allies, the occupying forces put their main effort into land defences aimed at repelling a seaborne or airborne assault. The resulting construction work in the Channel Islands was extensive; it required thousands of workers and massive supplies of cement and steel. Tiny Guernsey received special treatment. It had the largest artillery pieces in the Channel Islands, tanks, and 12,000 troops: one soldier for every two civilians on the island, compared to France
Maritime history of the Channel Islands at La Hougue Bie, Jersey give evidence of either populations living on or visiting the islands. Guernsey and Alderney were separated from mainland Europe around 7,000 BC with Jersey some time after, but even at 4,000 BC the islands were close to the mainland coast for basic boats to move between islands. Archaeological evidence of trade from the Iron Age period is in evidence in the Islands, with goods manufactured on the western coast such as armlets, Breton pottery and amphorae from the Mediterranean indicating trade along the Atlantic coast from Iberia to Ireland. Armorica was the nearest trade zone.