City Wall

Already in the Bronze Age, before the time of the kings, many Canaanite cities were fortified with city walls and gates. Many of these cities remained in use in the Iron Age as well, in the time of the kingdoms of Israel and Judah.

City walls were made of brick or stone. The bottom layer could also be made of earth. The walls could be as much as 10 metres thick. Often battlements were made on the top of the walls. The walls were reinforced with towers, from which attackers could be shot at.
Because the city walls were so wide, it was possible to make a further storey with rooms on top of the walls. According to the story in Joshua 2:15, Rahab lived in a house like this on the city wall of Jericho.

Until the ninth century BC, the city walls were often of the casemate type. Casemate walls consisted of two walls built approximately 1,5 to 2 metres apart. They were connected to each other by transverse walls, creating narrow in-between rooms. These spaces were sometimes filled with rubble, to reinforce them. But they were also sometimes used as storage space, or even as the back rooms of houses built up against the wall.
The advantage of this kind of wall was that relatively little material was needed for it. So it was not so expensive to build them.

From the eighth century BC onwards the cities of Israel were increasingly threatened by the Assyrians. The casemate walls were not strong enough to resist their battering rams and other weapons of attack. In the eighth and seventh centuries, the city walls were therefore made solid, often with indented and projecting parts.