View Images NG Maps

This story appear in the March/April 2017 issue of National Geographic History magazine.

While probing the depths of the Black Sea last year, a team of scientists made a surprising discovery, one that they weren’t even looking for. The group had been investigating the effects of sea-level change on early human societies, but after their underwater cameras probed the depths of the Black Sea they quickly saw why the Greeks nicknamed it the “Hostile Sea.” In its deep, dark waters, ancient shipwrecks are scattered across the seafloor.

Submerged Surprises

At first, wreck-spotting was far from the minds of the Maritime Archaeology Project (MAP) team, who started surveying the seabed off the coast of Bulgaria. Partnering with maritime archaeologists from across Europe and the United States, MAP’s mission was to study how sea-level change affected early human societies around the end of the last ice age, about 12,000 years ago.

As Earth warmed and glacial ice melted, sea levels rose. Water from the Mediterranean spilled over into Asia Minor, creating the Black Sea. While studying these environmental changes, the MAP team’s remotely operated vehicles (ROVs) stumbled on the first of the wrecks that lay untouched on the bottom.

Watch Incredibly well-preserved shipwrecks found in the Black Sea

View Images The wreck of a 13th-century Venetian cocha. Photograph by EEF, Black Sea Map

Preserved at Sea

More than 40 shipwrecks dating across a millennium were identified. The earliest is from the 800s, during the Byzantine Empire, and the rest largely date from when the sea was under Ottoman rule, from the 14th to the 19th centuries.

These ships offer historians new insights into the commercial networks that linked Europe with its eastern trading partners. Braving the Hostile Sea to bring grain, cattle, wine, and textiles to European cities was clearly a dangerous enterprise.

View Images Venetian explorer Marco Polo (1254-1324), depicted in a mosaic at the Palazzo Tursi, Genoa, Italy Photograph by Album

The Black Sea holds one of the best examples of a medieval variety of Venetian ship, which probably sank sometime in the 13th century. The lights of an ROV picked out the vessel’s distinctive quarterdeck, identifying this wreck as a cocha, or “round ship.” If, as the team believes, this boat served the Venetian empire, then the ill-fated cocha would have sunk during Venice’s golden era—the period when Marco Polo recorded his adventures.

Of great interest to scientists are the artifacts. In most oceans, ropes and spars are rapidly consumed by oxygenated waters, but in the Black Sea oxygen is entirely absent below depths of 500 feet. These delicate remains have been perfectly preserved.