The Answer:

The Hunley was an iron submarine named after one of its biggest investors. It was a secret weapon created in the South that designers hoped would help bring an end to the Union blockade during the Civil War.

The Hunley was launched in mid-July 1863. It sank twice during routine dives (killing most or all of two crews) before its encounter with the U.S.S. Housatonic on Feb. 17, 1864.

Here's the encounter as told on the Hunley's official web site: "With bullets bouncing off the Hunley's iron hull, (Lt. George E) Dixon guided the sub into the attack. With a jolt, the Hunley's torpedo spar was rammed into the side of the mighty ship. The crew quickly reversed their course, backing away to allow a safe distance from the ship before the tripline detonated the 90 pounds of explosives affixed on the torpedo spar. For some unknown reason, the torpedo detonated prematurely."

The Hunley made history by becoming the first submarine to sink a ship in battle, but what happened after that attack is still a mystery. The submarine and crew disappeared and its location wasn't known for over 130 years.

On May 4, 1995 archeologists from the National Underwater Marine Agency, an organization founded and funded by best-selling author Clive Cussler, discovered the Hunley in shallow water off the coast of Sullivan Island north of Charleston, S.C.

For more information, check out the official Friends of the Hunley website.

—The Editors