A team of archaeologists diving near the Greek island of Antikythera have reported a startling new discovery from a previously explored 2,000-year-old shipwreck. The find — a very heavy, metal cylinder — offers new insights into the maritime warfare of ancient times, the scientists say.

“Of the 40 or 50 shipwrecks all around the Mediterranean, "there’s nothing like the Antikythera,” says Brendan Foley, an archaeologist from the Woods Hole Oceanographic Institution. He’s only recently returned from exploring the ruined ship, which now sits nearly 200 feet beneath the surface, encrusted with sediment and sea life.

Ancient Shipwreck Off Greek Island Yields A Different Sort Of Treasure

Antikythera team members Nikolas Giannoulakis, Theotokis Theodoulou, and Brendan Foley inspect small finds from the shipwreck, while decompressing after a dive of 165 feet beneath the surface of the Mediterranean Sea in Greece. Brett Seymour/EUA/WHOI/ARGO