A vaulted ceiling thought to date from Roman times—perhaps from the Herodian period (37–4 B.C.E.) or later—covers the steep, uppermost portion of the Warren’s Shaft system, indicating that this water system continued in use long after Hezekiah’s tunnel had been constructed. The iron steps, built when the tunnel was recently opened to the public, conceal steps hewn into the original floor. The upper tunnel of the Warren’s Shaft system follows a semicircular course that lengthens the 82-foot, straight route to 136 feet. There is no apparent engineering reason for this design, which supports the author’s belief that the builders adapted a natural tunnel.