Forensic Case: SS Hunley

In April 1861 a pent-up fury that had been brewing for a century, shattered America's grand republic. Three years later, on a cold February night in 1864, one of the Civil War's most secret weapons - the Confederate submarine H.L. Hunley - set out from, under the command of George Dixon.

The Hunley successfully attacked and sank the Union warship, Housatonic. Then the submarine disappeared into the waters of South Carolina, never to be seen again.

The Hunley was both primitive and innovative; a submersible that was inspired by the ideas of a chemist and minister named Franklin Smith, and largely funded by wealthy plantation owner Horace Hunley.

The submarine was a converted 40-foot iron steam boiler tapered at both ends, just four feet high and three feet wide. The crew squeezed through two tiny hatches and, when submerged, their only air supply was sealed in with them.

A candle provided light. When the candle died, the crew knew their oxygen was almost depleted. Desperate times called for bold measures.

Now, 138 years later, the Hunley has been found. In this programme archaeologist Bob Neyland and his team plan to raise the submarine - in one piece.

Why did the Hunley sink? What artifacts are still on board? With help from more than forty archeologists, divers and engineers, the team hopes to solve one of the Civil War's greatest mysteries.