If you like this kind of "architecture" you should definitely visit Rocroi if you ever happen to be in (the north of) France:
https://maps.google.com/maps?hl=en&ll=49.925021,4.520338&spn...
edit:
Palmanova in the north of Italy also looks nice:
https://maps.google.com/maps?hl=en&ll=45.905658,13.310108&sp...