amphitheatre of basalt columns at giant causeway, volcanic rock layers framed by cliffs, greenery

amphitheater amphitheatre ancient atlantic basalt basaltic causeway cliffs coastal columns dramatic erosion famous formation geological geology giants green heritage hexagon hexagonal iconic ireland landmark landscape layers natural nature northern outdoors rocks rugged scenic summer tidal tourism travel unique volcanic wild world this giant#39aph39#s reveals rock formed millions years ago framed vegetation steep giant#39aph39# greenery giant