When it was raised in 2000, the HL Hunley looked a bit like the Flying Dutchman. Encrusted in a rock-hard layer of sand and shell, the hand-powered Civil War submarine that slumbered off Charleston, SC, for almost 140 years had to be painstakingly soaked and cleaned. But after three years of scrubbing, the first sub to sink an enemy ship is finally beginning to gleam. "It looks like a submarine now, as opposed to a corroded artifact," Michael Scafuri, the lead archaeologist of the project at Clemson University's Warren Lasch Conservation Center, tells the Post and Courier. Most of the concretion that remains is in the interior, but even that is being peeled away to reveal gears, cranks, and some surprises—like a human tooth.
Scafuri tells WCSC that the tooth, corroded to the iron of a crank handle, belonged to crew member Frank Collins, who was found to be missing several teeth when his remains were buried in 2004. It would've detached long after the Confederate sub sank on Feb. 17, 1864, just after downing the Union's Housatonic. Removing layers of debris also revealed cloth and metal on cranks that would've protected hands from chafing, but why the sub sank remains a mystery. "We will always have an element of uncertainty," says Scafuri. For now, "everything is on the table within reason." A 2016 study determined it was unlikely that the crew members suffocated and that the sub sank as a result, per the Charleston City Paper. (Here's another theory.)