The newer Siloam Tunnel, also known as Hezekiah's Tunnel, is a water tunnel that was carved within the City of David in ancient times, now located in the Arab neighborhood of Silwan in eastern Jerusalem. Its popular name is due to the most common hypothesis that it dates from the reign of Hezekiah of Judah, late 8th and early 7th century BC, and corresponds to the "conduit" mentioned in 2 Kings 20 in the Hebrew Bible. According to the Bible, King Hezekiah prepared Jerusalem for an impending siege by the Assyrians, by "blocking the source of the waters of the upper Gihon, and leading them straight down on the west to the City of David". By diverting the waters of the Gihon, he prevented the enemy forces under Sennacherib from having access to water. An older water system, sometimes called the Siloam Channel, partly fulfilled a similar purpose and dates back to the Canaanites.

Gihon Spring or Fountain of the Virgin, also known as Saint Mary's Pool, is a spring in the Kidron Valley. It was the main source of water for the Pool of Siloam in Jebus and the later City of David, the original site of Jerusalem.