In July 2010, amid the gargantuan rebuilding effort at the site of the World Trade Center in Lower Manhattan, construction workers halted the backhoes when they uncovered something unexpected just south of where the Twin Towers once stood.

At 22 feet (6.7 meters) below today's street level, in a pit that would become an underground security and parking complex, excavators found the mangled skeleton of a long-forgotten wooden ship.

Now, a new report finds that tree rings in those waterlogged ribs show the vessel was likely built in 1773, or soon after, in a small shipyard near Philadelphia. What's more, the ship was perhaps made from the same kind of white oak trees used to build parts of Independence Hall, where the Declaration of Independence and U.S. Constitution were signed, according to the study published this month in the journal Tree-Ring Research.