On the night of February 17, 1864, the tiny Confederate submarine HL Hunley made its way toward the USS Housatonic just outside Charleston harbor. Within a matter of hours, the Union ship?s stern was blown open in a spray of wood planks. The explosion sank the ship, killing many of its crew. And the submarine, the first ever to be successful in combat, disappeared without a trace. For 131 years the eight-man crew of the HL Hunley lay in their watery...