My hometown was as many other places during WW2 a place of strategic importance. And to be able to protect it during its occupation the Germans made a lot fortifications.
There structures still exists today, and here are some images.
This is a small bunker
A searchlight for locating planes
A artillery gun
One of the underground caves that connects the different parts of the fortification
Here are a small movie that shows how the fortification looks from the inside, it is no light, and the filming is not that good, but I hope you get an ide of how it looks.
Here you have a overview image of the site, and you can se the strategic value with the town in the background, and its proximity to the shipping lanes.