A view of Hadrian's Wall at the Birdoswald Roman Fort near Gilsland, England.  The fort is just out of view, yet it was known as Banna ("peak, horn" in Celtic) in Roman times, reflecting the geography of the site on a triangular spur of land bounded by cliffs to the south and east commanding a broad meander of the River Irthing in Cumbria below.  This section of Hadrian's Wall is the longest surviving stretch & was originally built using turf starting in 122 AD.  The fort was occupied by Cohors I Aelia Dacorum and by other Roman auxiliaries from approximately 126 AD to 400 AD.  The two-mile sector of Hadrian's Wall either side of Birdoswald is also of major interest. It is currently the only known sector of Hadrian's Wall in which the original turf wall was replaced, probably in the 130s AD, by a stone wall approximately 50 m (160 ft) further north, to line up with the fort's north wall, instead of at its east and west gates. 

More info here: https://en.wikipedia.org/wiki/Banna_(Birdoswald)