Bulgarian archaeologists claim to have discovered Europe's oldest prehistoric town in the north-east of the country.
The town, near the salt pans of Provadia, in the Varna region of Bulgaria, is located in the same area as Europe's first salt factory.
The archaeology team, led by Professor Vasil Nikolov from the National Archaeology Institute and Museum, have been studying the area for many years and believe the key to the town's success was its natural abundance of salt which, at the time, was as valuable as gold.
Professor Nikolov said: "Now we can say that the Provadia salt pans' location is the oldest town in Europe, it existed between years 4700 to 4200 BC, in the second half of the fifth millennium before Christ."
"What makes a difference here from all the other ancient villages in south-east Europe are the salt springs ... the salt produced was used as money because salt was essential for humans and animals as well.
"So salt production was what made this village different from others and gave it prosperity," Nikolov added.
Signs of wealth were also found in the ruins, with fragments of copper hair accesories found amongst the skeletal remains.
The inhabitants of the settlement, in north-west Bulgaria, boiled brine from salt springs in kilns, then baked it into bricks and used it for trading.
Professor Nikolov's discoveries have been confirmed so far by scientists from Japan, Great Britain and Germany, who have closely followed research connected to the Provadia salt pans.