The town of Cardona, located in the north of the province of Barcelona, became widely known in the Middle Ages and brought to the heights the wealth of its city rulers thanks to extensive (for those times) salt deposits, namely its famous Salt Mountain (Montaña de Sal).
Unfortunately, only a small hill remains from the mountain nowadays . But modern tourists are offered to make a tour of the underground galleries of the salt mining enterprise existing here before 1990 and enjoy the sights of the fantastic tangles of salt minerals.
A detailed story about the history of the Salt Mountain in Cardona and some photos (you are allowed to take photos only in a few places inside) can be viewed following the link.