Joshua and the Walls of Jericho

The battle of Jericho is a story familiar to any child who grows up in a Christian home. But a closer look at the narrative reveals details that are more suited to a mature audience. We are told that, after the walls came down, every living thing in Jericho men and women, young and old, and all beasts were slaughtered. How can that be justified? Especially if the battle of Jericho is meant to be an example of heroic faith (Heb 11:30). What are we to learn from this peculiar victory of God's people that was marked by such violence and destruction?