Photo: A tourist inside Hezekiah's Tunnel in Jerusalem, Israel
Hezekiah's Tunnel, also known as the Siloam Tunnel, was dug underneath the Ophel (the elevation in two cities: the City of David in the Old City of Jerusalem and at Samaria, the ancient capital of the Kingdom of Israel) before 701 BC during the reign of King Hezekiah. He (alternatively: Ḥizkiyyahu, Yeẖizkiyyahu, Ḥizqiyyā́hû, Yəḥizqiyyā́hû, Ezekias, or Ezechias) was the son of Ahaz and the 14th King of Judah who is believed to have reigned between 715 BC and 686 BC. It is one of the oldest structures in the world that the public can visit and walk through.
Both the written Siloam inscription found in the tunnel and dating the organic matter in the original plaster in the tunnel shows it as an 8th century BC structure. Leading from the Gihon Spring to the Pool of Siloam, the 533 meter long curved tunnel was designed as an aqueduct to provide water to Jerusalem during an impending siege by the Assyrians. According to the Siloam inscription, the tunnel was dug by two teams from each end and they met in the middle. However, scholars of recent times suggest that the tunnel might have been created by widening a pre-existing natural karst.