 The 14-metre shaft is too narrow, and the pool at its base too shallow, to have been functional, and archaeologists now believe that it is merely a natural fissure that the original excavators happened to breach during their dig towards the other pool.In 1998, while a visitor centre was being constructed, builders discovered that there was an additional passageway, about 2 metres higher and starting from the horizontal curved tunnel, that skirted the 14 metre vertical shaft, and continued to a pool much nearer the Gihon spring.The higher passageway was not originally higher—at some point Warren's shaft was lowered (cutting into a geologically distinct type of rock), and ran into the 14-metre vertical shaft.