star-d bastion walls of suomenlinna fortress at kustaanmiekka island

19th ancient archeology archipelago architecture baltic bastion been century channel coast culture defense early environment europe finland fortification fortified fortress grass green guard guarded gulf have helsinki hill historic historical history island islands kustaanmiekka landmark landscape narrow natural nature park raised remains rock ruins scenic sea seascape sky southernmost star starshaped stone strait suomenlinna sveaborg travel walls water