During the American Civil War, huge metal monsters roamed the Mississippi River. Called ironclads, these boats were about 50 yards long, carried 75 tons of armor on their hulls and decks, sported up to 13 guns, and had crews numbering up to 250 men.
The seven city-class ironclads, sometimes called the turtles, were the most recognizable boats in the fleet, but northern laborers also converted a few existing steamboats into armored vessels.
The Union used this cutting-edge naval technology to attack Confederate forts at places like Tennessee’s Fort Henry and Island No. 10, and Vicksburg, Mississippi.