Hezekiah, king of Judah, fortified Jerusalem at the end of the 8th century BC, just before the invasion of Sennacherib. As part of his building project, Hezekiah brought water into the city of Jerusalem through a tunnel carved from over half a kilometer of bedrock (2 Kings 20:20). A six percent gradient was designed into the excavation to allow water to flow from the Gihon spring into the pool of Siloam (compare John 9:7).
The Babylonian Chronicles are a series of clay tablets inscribed with Babylonian history. They were written at different times, beginning around the sixth century BC. They narrate events beginning in the eighth century BC and cover nearly 500 years of history. Some describe events of biblical history—including Jehoiakim’s refusal to pay tribute (2 Kgs 24:1), Nebuchadnezzar’s siege of Jerusalem (2 Kgs 24:10–11), and Jehoiachin’s capture (2 Kgs 24:12).
 Hubbard, Shiloh, Elliot Ritzema, Corbin Watkins, and Lazarus Wentz with Logos Bible Software and KarBel Media. Faithlife Study Bible Infographics. Bellingham, WA: Logos Bible Software, 2012.