17th century access arch architecture Argolis castle defence defense elements entrance fort fortress Greece historical landmark Morea nafplio old Palamidi Peloponnese power stairs steps stone stronghold venetian ancient arrow slots building curved defend defensive Girona light protect security shadow Spain spanish turret walls blocks Golan Heights Israel Mivtzar Nimrod Nimrod Nimrud Qal'at Namrud Remains ruins battlements Cornish cornwall dominion England english Great Britain Michael mount national trust rock saint St. Michael's Mount tower London Norman tourism tourist attraction Tower of London turrets hilltop ramparts view beam bricole Castelnaud-la-Chapelle catapult dordogne France machine mediaeval perrière sling throw trebuchet war weapon