Hezekiah's Tunnel, also known as the Siloam Tunnel, is an ancient tunnel dug under the City of David in Jerusalem by King Hezekiah of Judah. The tunnel is mentioned in the Tanakh in the Second Book of Kings and Hezekiah's success in bringing water to Jerusalem is referred to in the Second Book of Chronicles.
Hezekiah used the tunnel to block the water supply to the the Assyrians who were going to attack the city and were outside.
About 27 centuries later the tunnel, was excated and found by archaeologists. A Biblical Siloam inscription was found in the tunnel proving that it was Hezekiah's Tunnel.