Monday marked the 150th anniversary of the Confederate submarine H.L. Hunley's sinking of the Union warship Housatonic off the coast of Charleston, South Carolina. The Hunley also sank during that historic mission and remained submerged until 2000. Today, the submarine is kept in a laboratory in North Charleston where visitors can see it and researchers continue to explore the events of a century-and-a-half ago. WFAE's Mark Rumsey discussed that research with Dr. Stephanie Crette, director of Clemson University's Warren Lasch Conservation Center, which is helping supervise the restoration work.