Fourni, a Greek archipelago close to Turkey in the eastern Aegean Sea, recently became a location of interest because of statements by local fishermen and sponge divers who had seen piles of ancient pottery collecting algae on the seafloor. Two months ago, a group of marine archaeologists finally investigated the waters, and their wealth of findings far exceeded expectations.

During the very first dive of the expedition, the team found the remains of a late Roman-period wreck strewn with sea grass in shallow water. By day 5, the researchers had discovered evidence of nine more sunken ships. The next day, they found another six. By the time the 13-day survey was finished, the divers had located 22 shipwrecks--some more than 2,500 years old--that had never been scientifically documented before.

The expedition turned up doomed vessels from the Archaic period (700-480 B.C.) to the late medieval period (16th century A.D.), from depths of 180 feet (55 meters) to as shallow as 10 feet (3 m). And yet, this initial survey covered merely 17 square miles(44 square kilometers), just 5 percent of the archipelago's coast. Previously, about 180 ancient shipwrecks had been well-documented in all of Greece's territorial waters. These new discoveries add 12 percent to the total number of known wrecks.

Of the 22 newly discovered wrecks, three have unique cargos that have never been found before in Mediterranean shipwrecks: a trove of Archaic pots from nearby Samos that was probably destined for Cyprus, but didn't make it very far; a group of huge second-century A.D. amphoras from the Black Sea region; and a cache of "Sinopian carrots," or amphoras that come from Sinop on the Black Sea coast of Turkey and, as the name implies, are shaped vaguely like carrots.

Archaeologists mapped each wreck using photogrammetry to create 3D site plans. Representative artefacts were excavated and raised from each wreck site for scientific analysis. These artefacts are primarily amphoras, which were terracotta jars that carried bulk goods prior to the invention of wooden barrels. The finds are currently undergoing conservation at the Ephorate's laboratory in Athens and may go on displays in museums in the future.

Fourni is a collection of thirteen islands and islets located between the eastern Aegean islands of Samos and Icaria. The small islands never hosted large cities, instead their importance comes from their critical role as an anchorage and navigational point in the eastern Aegean. Fourni lies along a major east-west crossing route, as well as the primary north-south route that connected the Aegean to the Levant. Early Imperial Roman sources say that Fourni was very prosperous, had a robust population and had marble mines in full operation. But mentions of the archipelago in late Roman texts are scant, which is why the divers were surprised that about half of the wrecks found in the survey date to this period.

Less than five per cent of Fourni's coastline has been explored for underwater cultural heritage. Local fishermen and sponge divers have reported many more leads that will be followed up in future seasons. The team plans to return next year.

For many pictures of te dive and its findings, go here.