Walls demarcate frontiers, deter predators, and
protect people and their families and possessions.
Stone walls punctuated by towers and gates have surrounded cities in the
Middle East and North Africa since biblical times, when
fortifications were often built in concentric rings and outlined by a
ditch or a moat for added protection.
Walls were a prominent feature of many medieval and early modern cities;
from Baku to Delhi to York to San Juan, visitors still relive a past
when constant vigilance and strong defenses were a feature of daily...