During this year's excavation in Europe's oldest salt mines near Provadia, eastern Bulgaria, archaeologists discovered a wall from the fifth millennium B.C.E.

According to the head of the expedition, Vasil Nikolov, quoted by the Bulgarian National Radio (BNR), the new discovery suggests that mining activities in the area were much more significant than previously thought.

“This was a fluke, as many archaeological discoveries are,” Nikolov told BNR. “We found this wall, which in some parts is more than a metre high, but the rest was destroyed by an earthquake. I cannot yet say how tall it really was, but in its base it is more than three metres thick. But there are other walls in the area, which are almost four metres high. Just imagine – this is from the middle of the fifth millennium B.C.E. and there were no fortresses in Europe back then.”

During this year's archaeological season in Provadia, were discovered 10 funerals in the necropolis.