The answer is STOCKADE
who built a defensive wall was hadrian
It was not a defensive position or option, it was a prison wall.
A defensive wall.
Palisade or stockade.
In China they used the wall for protection from surrounding countries.
Because a wall alone is not enough to keep invaders out unless the wall is guarded.
Hadrian
The Qin empire build a long defensive wall and canals and standardized wights and measures.
Now-a-days it is a tourist attraction. In centuries past it WAS ( not IS) a defensive wall.
As a series of trading posts and defensive fortifications of the Dutch West India Company.
a defensive wall built by emperor Hadrian to seal off much of what is now Scotland from the romanized South.
No, ade is not a metric measure.