This old 1913 fortress was once part of the defence line for Amsterdam. It's located between Amsterdam and Dan Helder, right in the middle of the area that the 1799 Anglo-Russian invasion of Holland was fought over. So, Calantsoog, Castricum, Bergen, Alkmar and so forth are all within just a short drive away from the fort.
The GOOD news is that the fort is now a hotel, and I've booked us in for a couple of nights next month to break our journey on our way down to Crisis in Antwerp on 4 November. The rooms open up onto the old ditch and many of the original fortress features have been retained. I am looking forward to the visit.