Answer: Clay Pots

There are an estimated 3 million shipwrecks littering the oceans, lakes, and waterways of Earth. Most of their evidence has been eaten away over the years by chemical and mechanical action. The best place to preserve a wooden ship is, most certainly, not the bottom of the ocean.

The oldest shipwrecks, then, are not identified by the ships themselves—which in most cases have long since decomposed—but by their cargo. In the case of shipwrecks where the cargo was much hardier than the ship carrying it, we are able to identify the site of the wreck by its presence. Such is the case with the world’s oldest identified shipwreck, the Dokos shipwreck, located off the coast of southern Greece near the island of Dokos in the Aegean sea.

The ship and everything on it that was biodegradable—rope, leather, cloth, etc.—is long since gone. What remains is a pile of hundreds of clay pots and ceramic items; items impervious to the salt water they’re preserved in. The site was discovered by Peter Throckmorton in 1975 and, in addition to the huge cache of pots, additional artifacts were later recovered from the site. These artifacts include stone anchors, wide-mouthed jars, household utensils, millstones, and other items that suggest the vessel was a trading ship traveling the Mediterranean laden with merchant cargo.