City of David excavations
The City of David is surrounded on 2 sides by valleys. David took use of this as a stronghold of Zion. The Palace of David has been found, with large terraced retaining walls holding it up (called Milo). This is probably where the prophet Jeremiah was later kept. The Gihon Spring, where Saul was coronated was outside the city, so Hezekiah built a tunnel to channel it into the city and he disguised the spring itself.
The tunnel was built by two teams that started on ends of each other, they dug and hacked away at the rock until they met and put up a plaque. We walked down the upper portion of the tunnel, and it was amazing how even with all the twists and turns the two teams still met! I got to go behind Mr. Payton!