The legendary Blackbeard once sailed the seas as a real pirate of the Caribbean. But after his ship Queen Anne's Revenge sank off the coast of North Carolina in 1718, its wreck lay undisturbed on the ocean floor for nearly three centuries. Since the ship's discovery in 1996, thousands of artifacts have been brought to the surface -- including 5 of Blackbeard's cannons. The cast-iron guns weighed between 2,000 and 3,000 pounds each.