The waters of the spring still flow through the tunnel that King Hezekiah dug (701 BC) through solid rock to bring the waters to the west side of the city. The Upper Pool was cut into the bedrock, more than a thousand years before by the Canaanites and was filled by the spring through a channel cut into the bedrock. Hezekiah originally designed his tunnel to begin at the rock cut pool (tunnel IV) and end at the Siloam Pool. (Pool to Pool), (Upper Pool to Lower Pool).