Captain Morgan's Cannon?
The newly recovered cannon is among six believed to have belonged to the fleet of 17th-century buccaneer Capt. Henry Morgan, whom later accounts painted as a bloodthirsty pirate.
In 1671 Captain Morgan's current flagship, Satisfaction, hit a rocky reef and sank as he sailed out of the mouth of the Chagres River en route to sacking the Panama Viejo, now called Panama City.
Three more of Captain Morgan's ships either slammed into the same reef or collided with each other and also went down. But the determined Welsh privateer reassembled what remained of his fleet and continued on to plunder the city. Privateers were private sailors under contract to states—in Captain Morgan's case, Britain.
In 2008 an international team of archaeologists found the ships—and their cannons—that sank on that disastrous day. In 2010 the scientists began bringing cannons and other artifacts to the surface, where they'll be treated to remove organic buildup and then displayed in Panama.
(See exclusive pictures: "Blackbeard Pirate Relics, Gold Found.")
The project was a collaborative effort that included the government of Panama, the Waitt Institute for Discovery, the National Oceanic and Atmospheric Administration (NOAA), Texas State University, and the National Geographic Society. (The Waitt Institute sponsors the Waitt Grants Program for the Society, which also owns National Geographic News.)