The most ancient salt production factory in Europe and the oldest seismic event documented to the region of Provadia

About 5400 BC, the Neolithic people started to produce salt to meet their needs, at a place called now Provadia. A large salt body served as a source of this prehistoric factory, that produced the most important and vital product of the early farmers. This unique site in Europe excavated by the team of Prof. Vassil Nikolov shows the history of this place. Huge industry was developed and functioned more then 1000 years. Thick walled pots and hearths for the brine evaporation have intensively been produced, and can be seen now. It is possible to consider the prehistoric earthquake that occurred about 7000 years ago and destroyed the Chalcolithic dry-stone fortifications as a natural hazard interrupting for some time the salt production. A lot of facts, evidences and a hypothesis about such an event are presented to support this conjecture.