A Greek merchant ship discovered more than a mile under the surface of the Black Sea has been radiocarbon dated to 2,400 years ago, making it the world’s oldest known intact shipwreck. The vessel was located by the Black Sea Maritime Archaeology Project as they surveyed the seafloor some 50 miles off the coast of Bulgaria with a remote deep-sea camera system.

The 75-foot-long wooden ship remains remarkably well preserved because the Black Sea’s depths are oxygen-free. This has allowed experts to examine elements of ancient ship construction for the first time, including the design of the mast, twin rudders, and rowing benches. “A ship, surviving intact, from the Classical world is something I would never have believed possible,” says Jon Adams of the University of Southampton. “This will change our understanding of shipbuilding and seafaring in the ancient world.”