"And when Hezekiah saw that Sennacherib had come and intended to fight against Jerusalem, he planned with his officers and his mighty men to stop the water of the springs that were outside the city; and they helped him. A great many people were gathered, and they stopped all the springs and the brook that flowed through the land, saying, "Why should the kings of Assyria come and find much water?" (2 Chronicles 32:2-4 RSV). This occurred about 701 B.C.
King Hezekiah needed a reliable water supply for Jerusalem, but at the same time he wanted to prevent the Assyrian forces from using the Gihon Spring, which was located outside the city. The Bible records Hezekiah's solution: "This same Hezekiah closed the upper outlet of the waters of Gihon and directed them down to the west side of the city of David." (2 Chronicles 32:30 RSV).
The water from the Gihon was diverted into the Gai wadi by means of a tunnel 1,740 feet (530 meters) long. The tunnel work was done simultaneously from both ends, perhaps guided by an existing crack through the solid rock, until they met somewhere near the middle. It was a rather amazing feat of engineering for the time, as seen in the photograph above.
In 1880, an inscription was discovered by a boy who was bathing in the Gihon Spring. Carved in the rock at the end of the tunnel, it described the meeting of the two groups of workers who had started from opposite ends of the tunnel. Translated, it read "The tunneling was completed... While the hewers wielded the ax, each man toward his fellow... there was heard a man's voice calling to his fellow... the hewers hacked each toward the other, ax against ax, and the water flowed from the spring to the pool, a distance of 1,200 cubits..." The inscription is now in the Istanbul Museum.
And what happened to the Assyrian invaders?
A great force of Assyrians did indeed besiege Jerusalem. They called out taunts to the people inside the city, and went so far as to blasphemously insult The Lord - no doubt, their greatest error. Hezekiah prayed to God for deliverance. "And the angel of The Lord went forth, and slew a hundred and eighty-five thousand in the camp of the Assyrians; and when men arose early in the morning, behold, these were all dead bodies" (Isaiah 37:36 RSV). Sennacherib then retreated to Nineveh with what little remained of his forces. There, 17 years later, he was assassinated by two of his own sons, Adrammelech and Sharezer (Isaiah 37:38).
Fact Finder: For whose sake did The Lord deliver Jerusalem from the Assyrians?