When scientists revealed last week that they’d finally worked out where the ship found under the World Trade Center site was constructed, the question on most peoples’ lips was, “What ship?”

Here’s the back story, for those who missed it. Four years ago, construction workers excavating for the basement of the new One World Trade Center building at Ground Zero came across an oak hull, about 7m below street level. The ship, which is nearly 10m long, was found just south of the location of the original towers: that’s why no one no one had come across it before. 

Since then, researchers have been trying to figure out where it came from, and now scientists from Columbia University seem to have some of the answers. Using tree-ring analysis, and comparing different species of oak, they’ve established that the ship was probably built from trees growing near Pennsylvania in around 1773, two years before the War of Independence started. They also found what they call “idiosyncratic aspects of the vessel’s construction”, which led them to believe it was built in a small shipyard; and an infestation of something called “shipworm”, which the ship probably picked up on a trip to the Caribbean.

The fact that these findings have been publicised better than the ship’s original appearance is a testament to the PR efforts of Tree-Ring Research, the journal which published the paper (it’s probably their biggest scoop ever). However, it’s still not clear how a ship the length of two cars came to be lodged deep underneath New York City.