Bulgaria archaeologists find Europe's most prehistoric town Provadia-Solnitsata 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. Highly valued by surrounding tribes, it may explain why ancient caches of gold jewellery and ritual objects have been unearthed in the region. A collection of 3,000 gold objects found 40 years ago at a necropolis near Varna represented the oldest trove of ancient gold treasure in the world. At a time when people did not know the wheel and cart, these people hauled huge rocks and built massive walls. What did they hide behind them? The answer was salt," Vasil Nikolov, a researcher with Bulgaria's National Institute of Archeology, told AFP. "Salt was an extremely valued commodity in ancient times, as it was both necessary for people's lives and was used as a method of trade and currency starting from the sixth millennium BC up to 600 BC," he said. The "town," known as Provadia-Solnitsata, was small by modern standards and would have had around 350 inhabitants. "We are not talking about a town like the Greek city-states, ancient Rome or medieval settlements, but about what archaeologists agree constituted a town in the fifth millennium BC," said Mr Nikolov.