Invented during the Civil War this weapon became very popular, powerful, and destructive. Its metal outer shell that covered the wood prevented cannon balls or other weapon from destroying the ship. This weapon could take out another ship if it was made of wood easily, but it was extremely hard for one ironclad to beat another. A famous battle that occurred between ironclads was when the Union ironclad, Monitor, met the Confederate ironclad, Virginia. These two ironclads fought for hours, but neither ship sunk declaring the battle indecisive.