In the Fourni archipelago of the Greek Aegean region, towering underwater cliffs descend into the darkness of the deep sea. Marine archaeologists comb these murky depths for objects made by human hands — a ceramic shard encrusted with sea sponges, or an ancient vase that an eel has claimed for its home.

Through the centuries here, human handiwork has been absorbed by its natural aquatic surroundings, with rock and reef steadily growing around any remnants of life from early Western civilization.

The seeming improbability, then, of finding substantive artifacts in the patchwork makes discovery all the more exciting.

“You’re constantly scanning in any direction,” Peter Campbell, an underwater archaeologist at the University of Southampton, told The Washington Post. “There’s this moment that you see something, a straight line that doesn’t look natural, and your eye kind of flips over. You realize it’s an ancient pot or ancient anchor, then you notice this stuff is everywhere.”

While undertaking a survey of possible wreckage around Fourni last month, Campbell and his team experienced this sense of wonder an unprecedented 22 times over.

When Campbell and the expedition’s co-director, Greek archaeologist George Koutsouflakis, arrived at the collection of thirteen islands and islets in mid-September, they had heard some rumblings of artifacts from ancient ships to be found in the area.

As luck would have it, they came across a shipwreck on their very first dive, which the team took to be “a good omen.” Over the course of less than two weeks — the duration of their survey permit — they would have been content to find three or four wrecks in total.

After the first five days, that number hit ten. Then, on a single day, they found an additional six.

At this point, overwhelmed with the unexpected fortune, they decided to stop looking for wrecks so they could focus on adequately recording information from the ones they had already encountered. But even this decision didn’t stop them from finding a few more by the expedition’s end, making the sum uncovered in just 13 days an astounding 22 shipwrecks.

During this short period, Campbell and Koutsouflakis’s crew of marine archaeologists, local fishermen, sponge divers and the occasional robot (read: remotely-operated vehicle) increased the total number of known ancient shipwrecks in Greece by 12 percent.

An announcement this week revealed that the survey, a collaborative effort between the Greek Ephorate of Underwater Antiquities and the Florida-based RPM Nautical Foundation, yielded shipwrecks dating from the Archaic Period (700-480 B.C.) through the Late Medieval Period (16th century), including some wrecks that are more than 2,500 years old.

The small and relatively obscure region may be “the ancient shipwreck capital of the world,” the release says.

While a comparable number of wrecks have been discovered in major harbor sites like Pisa, Copenhagen and London, Campbell said, this find is significant because there was no major settlement or port in Fourni, which was merely a popular passing-through point.

These shipwrecks, however, illustrate just how crucial a passageway the small archipelago was for seafaring merchants of the ancient times. The storms that ravaged the neighboring islands of Samos and Icaria were so fierce that sailors often took refuge in Fourni’s abundance of gentle bays. The archipelago lies along a major east-west crossing route, as well as the primary north-south path from the Aegean to the Levant.

The large number of shipwrecks found suggests not that Fourni was an uncommonly dangerous locale, but rather that it welcomed an immense volume of sea traffic over a long period of time. Campbell estimates that there was likely no more than one wreck every hundred years.

By the time scientists can reach wrecks of this kind, any organic materials — wood, clothing, bodies — have long been eaten away by their environment. A shipwreck, then, is comprised of several hundred pieces of pottery, indicating the bulk of a ship’s cargo, that fan out from a distinct area.

Campbell said all the wrecks they found were from typical merchant sailing vessels and not from any warships.

“That suits us pretty well,” he said. “These shipwrecks tell the story of the every day person, and we’re really interested in what life was like for the average sailor in 400 B.C.”

According to the archaeologist, the narrative that emerges is one of a unique marine culture, in which a global sensibility permeated not only the objects that were shipped, but also the demographic makeup of the sailing crews. These outfits were often multicultural and multilingual, and were even known to have their own “mixed” language — the singular speech of men who spent most of their lives on water.

The ships carrying the found wreckage were all following the same trade route, Campbell said. It was one that connected the North Aegean and the Black Sea region to the Levant, Cyprus, Palestine and Egypt.

While historical texts had previously given archaeologists a general idea of how merchants sailed these routes, the wreckage around Fourni allows their travels to be traced in a way that was never before possible.

“This is one of the top discoveries in terms of what it can tell us about ancient maritime trade,” Campbell said. By combining terrestrial studies with close analyses of the unearthed ceramics, it will be possible to reconstruct entire itineraries of ancient voyages.

The amphoras (tall containers with two handles and a narrow neck) created back then had designs that were distinctive to their originating nation-states, so piecing together those patterns could yield quite a comprehensive understanding of the various stops that each ship made on their voyages.

While most of the artifacts remain in the ocean to preserve the encompassing natural habitat, a few are undergoing conservation treatments to prepare them for further examination. Through residue analysis, scientists may be able to draw conclusions about what the amphoras contained. (There are already hints of this in their shapes: thin necks for wine, larger necks for fish sauce.)

Campbell and Koutsouflakis’s team are in the process of applying for a permit for next year’s survey in the same area, where they expect to continue finding shipwrecks.

This year’s excursion, however, is almost certainly an outlier.

“I don’t think I’ll ever get the chance again to come upon 22 shipwrecks in a single season,” Campbell said. “It’s really a once-in-a-lifetime discovery.”