There is a type 616 telephone bunker behind the old post office, near the station in Den Helder, one of the three remaining in The Netherlands. This mirror-built bunker is where the communication between the various defence posts in and around Den Helder was coordinated. Today it is a petite museum with an extensive collection.
GPS-coördinaten: 52.9566257, 4.7593005999999605
Boerhaavestraat 15, 1782 AA Den Helder, Nederland
No ticket salepoint (buy your tickets at one of the other locations)