Defensive wall
A defensive wall is a fortification used to defend a city from potential aggressors. In ancient to modern times, they were used to enclose settlements. Generally, these are referred to as city walls or town walls, although there were also walls, such as the Great Wall of China, Hadrian's Wall, and the metaphorical Atlantic Wall, which extended far beyond the borders of a city and were used to enclose regions or mark territorial boundaries. Beyond their defensive value many walls also had important symbolic functions — representing the status and independence of the communities they embraced.
Defensive Wall Media
9th century BC relief of an Assyrian attack on a walled town
The lakeside wall of the Yueyang Tower, Yuan dynasty
Medieval defensive walls and towers in Szprotawa, Poland, made of field stone and bog iron
The medieval Walls of Avila (Spain) are one of Europe's best preserved walls.
Remains of a defensive wall of Prince Qin Mansion, a citadel within Xi'an
The Stone City is a wall in Nanjing dated to the Six Dynasties (220~589). Almost all of the original city is gone, but portions of the city wall remain. Not to be confused with the City Wall of Nanjing.
Multiple barbicans of Tongji Gate, Nanjing