Fort Blauwkapel in Utrecht

You're standing at Fort Blauwkapel, just outside Utrecht. It's one of the largest forts of the New Dutch Waterline, the defence line that was meant to protect Holland. What makes it special is that there's a whole little village inside the ramparts. When the fort was built between 1818 and 1821, the hamlet of Blauwkapel simply ended up in the middle, with a moat around it all.