A cutaway of Jerusalem’s water system shows the position of Warren’s Shaft. Before the shaft was exposed in about 800 B.C.E., Jerusalem residents could walk down an underground tunnel to reach a large pool of water fed by the Gihon Spring. While enlarging that tunnel, the residents discovered Warren’s Shaft. They realized, author Faust contends, that if they used a platform at the top they could lower a bucket straight down to the water.