1 Kings 9:15

15Now this is the account of the forced labor which King Solomon conscripted to build the house of the Lord, his own house, the 9:15 The exact nature of the Millo is unclear, but most scholars believe it was some sort of military fortification such as a tower, a citadel, a significant part of a wall or even an earth-fill or terraced hillside. It was located on the eastern side of the City of David. It was later repaired by King Hezekiah.Millo (fortification), the wall of Jerusalem, [and the fortress cities of] Hazor, Megiddo, and Gezer.