 The pool reached by the higher passage was protected by a large tower, which was also discovered by the visitor centre builders, and is located outside the Bronze and Iron Age city.The pool connects to the Gihon Spring via a narrow channel, and the Gihon was itself protected by the already mentioned large tower.The pool itself may have been protected by a second tower, but this is uncertain as excavation of the southern side of the pool has not yet been carried out, since it lies under a current residential area.