View looking south at the final portion of the “Diagonal Tunnel.” This portion is just above the modern staircase.
In this area the tunnel is about 6.6 ft. [2 m.] high. Just left of center the tunnel turns to the left where it ends at the newly discovered ancient towers and pool.
The Diagonal Tunnel leads down, from within the ancient city, to a pool that was fed by the Gihon Spring, from which water was drawn. It evidently dates back to the Middle Bronze II Age (= ca. 1800 B.C.) and was used for many centuries.
For the most recent theory of how this tunnel system worked, and its date, see Reich, Ronny, and Shukron, Eli. "Light at the End of the Tunnel: Warren's Shaft Theory of David's Conquests Shattered." Biblical Archaeology Review, vol. 25, no. 1 (January/February, 1999):22–33, 72.