Warren's Shaft is a vertical shaft next to the Gihon Spring, the main source of water of Bronze and Iron Age Jerusalem, discovered in 1867 by British engineer, archaeologist and military officer Charles Warren. The term is currently used in either a narrower or a wider sense:In the narrower, initial sense, Warren's Shaft is the almost vertical natural shaft leading down to a pool fed by the Gihon Spring. In the wider sense, as the Warren's Shaft system, it is the Bronze Age water system allowing protected access from the city to the Gihon Spring.