Joshua 8:28-31

So Joshua burned Ai and made it forever a heap of ruins, as it is to this day. And he hanged the king of Ai on a tree until evening. And at sunset Joshua commanded, and they took his body down from the tree and threw it at the entrance of the gate of the city and raised over it a great heap of stones, which stands there to this day. At that time Joshua built an altar to the LORD, the God of Israel, on Mount Ebal, just as Moses the servant of the LORD had commanded the people of Israel, as it is written in the Book of the Law of Moses, “an altar of uncut stones, upon which no man has wielded an iron tool.” And they offered on it burnt offerings to the LORD and sacrificed peace offerings.