The German artillery battery situated at Longues-sur-Mer  is a classic example of the Atlantic Wall fortification, the actual guns are still in place and the visitor can go into the case mates which house them.
The whole area is very similar to Pointe-du-Hoc, with a forward observation bunker overlooking the cliff top.
I don't know if the Allies were aware of this battery, I have a feeling they weren't because during D-Day it was responsible for giving a terrific pounding to the Allied shipping, and also laid down fire on the British and Canadian beaches.

The German battery at Longues-Sur-Mer is open to the public all year round, guided tours can be taken from April to September.
A great place to visit whilst on the D-Day trail, you can actually enter the case-mates and the forward observation bunker.

The actual size of the case-mates can be appreciated when looking at these two photographs.
The 155 m.m.  Howitzer  had a terrific range, as the allied shipping found out!!

The field of view from the Battery observation tower was tremendous, here we can see, looking eastward, Gold Beach. Over the other side of the headland can be seen Juno Beach. If we could look westward we would see Omaha Beach.