Empires and Walls

Why do empires build walls and fences? Are they for defensive purposes only, to keep the 'barbarians' at the gate; or do they also function as complex offensive military structures to subjugate and control the colonized? Are the colonized subjects also capable of erecting barriers to shield themselves from colonial onslaughts?

In Empires and Walls Mohammad A. Chaichian meticulously examines the rise and fall of the walls that are no longer around; as well as impending fate of 'neo-liberal' barriers that imperial and colonial powers have erected in the new Millennium. Based on four years of extensive historical and field-based research Chaichian provides compelling evidence that regardless of their rationale and functions, walls always signal the fading power of an empire.