milecastle 39 along hadrians wall, northumberland national park, northern england, great britain

aelium ancient archaeological archaeology architecture attraction border borders britain britannia britannicus british britons building castle clouds empire england europe excavation fort fortification fortlets foundations frontiers garrison grass grassy great hadrian hadriani hadrians heritage hiking hills history kingdom landscape limes low masonry mile milecastle milefortlets national nature nestled nick northern northumberland park path pennines picts point post remains rigg roman rome scotland site square steel steep strategically structure tourist trail travel two unesco united vallum wall western world