aerial view kastelet, pentagonal start fort in copenhagen with restored moat, ramparts, ravelin, bridge over the moat

fortification architecture scandinavian scandinavia traditional attraction copenhagen historical kastellet landscape tradition undefined barracks building entrance exterior fortress historic landmark military ramparts tranquil waterway windmill citadel counter denmark milling machine outdoor tourism aerial danish europe nature shaped travel guard grass green north royal 17th army city fort gate moat park star old sky