This clifftop defensive position was built to protect the railway tunnel and line which skirts the south of the city and port of Boulogne.
The tunnel here was used to protect a Krupp-built K12 railway gun (similar to the one on display at the Batterie Todt Museum in Audinghen) which operated in this area during WW2.
Railway guns were located here from 1940 onwards originally to provide fire support for Operation Sealion (the German invasion of Britain) and later to fire 28cm shells across the English Channel to Dover.
In December 1940, Adolf Hitler visited the newly occupied region and spent the evening on his train inside the tunnel which protected him from bombing raids on the nearby port area.
Above the tunnel entrance you can see two small guardhouse buildings plus an open emplacement for a defensive 5cm KwK gun while further structures include an observation post and MG position located along the ridgeline overlooking the beach area and southern port.
In more modern times this was also the site of the Boulogne to Dover Hovercraft port and the railway line was used to transport passengers from the hoverport to the city.
You can still see the terminal and workshop buildings plus a large expanse of concrete where the craft would dock although the encroaching sand and dunes have now covered over the seaward side of the site.
The area has recently seen a new car park built so visiting the site is easy but it’s best not to venture too far in to the long, dark tunnel as it can be dangerous in places.