Land mines. Usually artillery shells buried in opportune places and fitted with pressure fuzes or concealed trip wires. First used in the Civil War by Confederate defenders at Yorktown in 1862.

Today called mines, Civil War torpedoes were mostly used by the Confederates. Sometimes they were buried in the ground in the enemy's path to explode when stepped on. Mostly they were used as water defenses. They floated below the surface of the water and exploded when the hull of a ship brushed against them.