Towers and Gates. Towers were built into the inner walls (in addition to bastions or towers in the outer walls). They were higher than the wall, protruding from the wall sometimes as much as 3 m (10 ft). They were equipped with crenellations on top and sometimes with openings below the crenellations, for the convenience of archers and stone throwers. The fact that the towers protruded from the wall and were never placed farther than two bowshots apart, but were usually much closer, enabled the defenders to command all the area along the wall. Also, a balcony at the tower’s top had openings in the floor so that archery fire, stones, and firebrands could be directed straight down at the invaders below. These towers are mentioned many times in the Scriptures. (Ne 3:1; Jer 31:38; Zec 14:10) Towers served also as posts for watchmen, who could see the enemy approaching from a distance.​—Isa 21:8, 9.

Usually the citadel was built on the highest elevation in the city. It had a tower fortress and its own walls, less massive than the walls surrounding the city. The citadel was the last stronghold of refuge and resistance. When the soldiers of the enemy breached the city walls, they would have to fight through the streets of the city to reach the tower. Such a tower was the one at Thebez, which Abimelech attacked after capturing the city and where a woman broke his skull by pitching an upper millstone upon his head.​—Jg 9:50-54.

Besides these city towers, other towers (Heb., migh·dalʹ; plural, migh·da·limʹ) were built in isolated places. These were constructed as “police stations” to protect wells or other water sources, highways, frontiers, communication lines, or supply lines. King Uzziah of Judah is noted for building towers in Jerusalem as well as in the wilderness; these apparently were erected to protect the cisterns that he built for watering his livestock. (2Ch 26:9, 10) Several of such towers have been found in the Negeb.

Symbolic Uses. Since the towers in the wilderness were the safest places of refuge for miles around, we can see the appropriateness of Proverbs 18:10: “The name of Jehovah is a strong tower. Into it the righteous runs and is given protection.” Also significant are the expressions in Psalm 48: “In [Zion’s] dwelling towers God himself has become known as a secure height. March around Zion, you people, and go about it, count its towers. Set your hearts upon its rampart. Inspect its dwelling towers, in order that you may recount it to the future generation.” (Compare Heb 12:22.) This would be especially meaningful to Jews who would look up at the great stronghold of Jerusalem situated on an elevation higher than nearly any other major capital city in human history, with its mighty walls of defense.