age ages ancient architecture bronze castro Celtiberian celtic cidás circular citania citanias cities cividades cliff culture defendable defensive elevation fort fortified hill hill-fort hillfort hilltop house houses iron maritime ocean oval peninsula place refuge rock rocks saavem sea security settlement wall walls water clouds countryside defence defense Dorset earthworks England english fortifications Great Britain green hill fort historical Hod Hill landmark landscape light nature old rural sky summer sunlight basket battlements castle flowers framed hanging highlands Inverness scotland scottish tower commanding decay desuetude fortress Greece Greek hills Mystras Remains ruins stone stronghold UNESCO World Heritage view blue bluebells bulbs Coney's Castle natural path spring track trail trees wild woodland 17th century Argolis Morea nafplio Palamidi Peloponnese power venetian above attraction distant fields headland keep monument ramparts ruin ruined scarborough tourist