Shipwreck hunter Steve Libert claims that he’s found the wreckage of Le Griffon, the first European ship to sail the upper great lakes. Le Griffon was a seven-cannon 45-ton sailing ship captained by French explorer René-Robert Cavelier, Sieur de La Salle. On a return trip from Green Bay, Wisconsin in 1679 the ship disappeared along with its 6-person crew and a cargo of expensive furs. Since then, shipwreck hunters have been searching for Le Griffon’s watery grave, and it is considered the "Holy Grail" of Great Lakes shipwrecks. Has Steve Libert finally found it?