Enormous Metalworking System, Including Bronze Age Weapons, Discovered Underneath Pyramid-Shaped Greek Island

A pyramid-shaped hill on the Greek island of Keros has revealed a complex system of drainage tunnels and metalworking from the 3rd millennium B.C. that was ahead of its time.

Researchers from the University of Cambridge worked with members of the Ephorate of the Cyclades and the Cyprus Institute on an Early Bronze Age site called Dhaskalio, according to a new University of Cambridge press release. Rising sea levels have turned Dhaskalio into an island, but a thin land bridge (now underwater) still connects it to Keros, a "not so popular" island, according to the Greek community newspaper, Neos Kosmos. The promontory is a protected site and uninhabited today, but was once widely known for ritual activities, according to the Guardian.

The island's ancient inhabitants painstakingly sharpened the promontory's natural pyramid shape by carving it into terraces, which they covered entirely with more than 1,000 tons of white stone imported from the neighboring island of Naxos. The end result was one of a "gleaming," unified monument looming over the Aegean sea. It's the largest known man-made structure built anywhere in the Cyclades during that time period, according to the University of Cambridge.

Yet the pyramid's striking exterior didn't tell its full story. When excavating staircases built into the lower terraces, the researchers realized that the site had been engineered with extraordinarily technical sophistication. They also discovered two metalworking sites, one of which still contained a lead axe and a mold used to make molten copper into daggers. Another room revealed the top of a clay oven—still intact—hinting at an additional workshop waiting to be discovered.

Because Keros contains no metal ore of its own, all the raw materials must have been imported from other islands or from the mainland.

"At a time when access to raw materials and skills was very limited, metalworking expertise seems to have been very much concentrated at Dhaskalio," excavation co-director Michael Boyd told the University of Cambridge. "What we are seeing here with the metalworking and in other ways is the beginnings of urbanization."

Boyd went on to explain that the finds signified the early days of distant populations becoming interdependent and an increase in agricultural and architectural development. Those more modern elements gradually replaced the original, more ritualistic uses for the site, meaning that archaeologists and anthropologists studying Dhaskalio will gain a better understanding on how and why its society evolved the way it did during what Boyd refers to as its "middle years."

The construction of the drainage tunnels preceded the advent of nearby Crete's renowned indoor plumbing system by 1,000 years, according to the Guardian. Whether the tunnels were meant for draining clean water or for draining sewage, the archaeologists are still figuring out.