Rear View of the 13-inch Mortar at Petersburg, Va., September 1, 1864 (U.S. Civil War) This artwork depicts a rear view of a 13-inch mortar, a large artillery piece commonly used in siege warfare during the U.S. Civil War. The specific piece is shown at Petersburg, Virginia, on September 1, 1864. The image was created as part of the extensive documentation of military equipment and activities related to the Civil War. This artwork serves as a historical artifact that offers insights into the weaponry utilized during this significant period in American history.