Scientists working with the Naval Historical Center (NHC) to try to solve the mystery of the Confederate submarine H.L. Hunley's disappearance in 1864, stumbled onto yet another mystery in December.

A view port on the left front side of the submarine is completely missing, possibly a catastrophic result of the Hunley's historic battle with the Housatonic.

Some have speculated Sailors aboard Housatonic may have shot out the view port, causing the submarine to fill with water. That theory fails to explain why scientists have not found any of the view port's glass inside the submarine. Mysteriously, they have also found no traces of the port itself. There is just a hole where it once was.