The unusually shaped concrete constructions high on the hillside at Equihen Plage to the south of Boulogne-sur-Mer, are part of an advanced radio guidance system developed by the Germans in WW2 to direct bombing campaigns over England.
The site, known as Stp265 Lungenkraut featured six similar bunkers, each supporting a large antenna on top.
Known as the Erika system, the antenna would broadcast a series of pulses which helped German bomber aircraft identify their position and direction during night-time raids.
There’s a second, similar site in Saint Pierre Église, east of Cherbourg, and both were built to a high standard of construction.
However, they were built too late in the war to be truly effective as by the time they were in operation the Luftwaffe was a shadow of its former self.
The constructions were so large scale that they were easily spotted by allied aircraft too and were regularly attacked.
Today you can still see five of the remaining buildings with all but two almost completely buried and overgrown. The sixth was located in the field behind the others.
A close up inspection reveals that many of the communication cables are still protruding from outlets in the outer walls of the two more accessible structures, although there is no access to the internal rooms they fed into.
In support of the Erika I bunkers you can also see the remains of two generator bunkers on the opposite side of the main road around the east of Equihen, and a L430A type garage and position for a 150cm searchlight. The site also once boasted several anti-aircraft emplacements to the south of the radio guidance builds but these have been covered by housing and vegetation.