kastel fortress in banja luka, bosnia

banjaluka banja luka bosnia castle fortress kastel herzegovina republika srpska serbian republic fort september summer europe balkans architecture building old historic travel tourism town city cities capital bosnian european union east south eastern southern outside outdoors exterior landmark historical medieval stone arch windows entrance gate gateway walls passage passageway roof stari grad traditional heritage monument fortified defensive tower turret stronghold 16th sixteenth century grounds grass tree bushes vegetation ivy crawler creeper plants grey cloudy inside interior main viewed