Situated just north of Le Crotoy in the Baie de Somme region, Bihen features three amazing-looking R688 casemates which were created to protect the bay area with their 170mm guns in place.
These are some of the most photogenic gun casemates on the whole of the Atlantikwall in Northern France - but this site is well off the tourist route and dangerous to visit.
Stp Firmin-Bihen HKB gun batterie can only be accessed with permission as it’s a working sand extraction facility and the bunkers are all located on private land.

One of the R688 casemates stands in the corner of a fishing lake and is completely waterlogged and inaccessible.
The second is almost buried by the remains of an old nursery greenhouse complex while the third is now resting at an alarming angle on the edge of a lake created by sand extraction.
With permission (and care) you can also see a blown up R134 type ammunition bunker, a small guard house next to the road, and the remains of a personnel/canteen building at this site.