The massive R688 casemates – four of a total of 33 built on the Atlantikwall in northern France – were constructed to ‘A’ specification, the heaviest concrete designation with walls up to 3.5m thick and a huge amount of reinforcing steel.
Built for 17cm cannons, the wheeled guns were mounted on turntables inside the casemates and the design allowed for 120 degrees of movement, giving them a wide coverage of the Canche river estuary and long beaches along the coast at Le Touquet.
The four casemates are heavily overgrown in the woods, so access is difficult unless you visit in the winter months. A R134 ammunition bunker was also part of the site and stood between casemates three and four, although it has been completely destroyed and it’s tricky to find any remains amongst the vegetation.
Inside the casemates you can see that the gunroom itself is huge – measuring 10m wide – and there are two rooms to the rear, one each for shells and cartridges which are either side of a corridor leading to the rear entrance which would have been protected by a heavy-duty steel door. Each cannon was protected from aerial damage by the R688’s characteristic reinforced hood overhanging the gun room.