In the lower center of the image is a small “orange” opening, this is where Warren’s Shaft descends vertically.
Notice on the right side of the image, above the metal banister, the two types of rock. The lower portion (browner) seems to be harder than the upper (whiter) rock. On the left side of the image the same two rock formations are visible.
Note too, just above the center of the image the large hole that is filled with large boulders.
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.