Said to contain three billion tons of salt, the Salina Praid salt mine, also called the Dealul Sarii, is located in Europe's "Salt Zone" and is one of Europe's largest salt mines.
Salt mining here dates back to Dacian times, a practice later exploited by the Romans. In the 1500s, the salt mine came under the control of Transylvanian Hungarians known as Szeklers (though they may have been Avars), who mined the salt three times a year, tax-free.
In the 1960s, the mine started to be used for therapeutic purposes, and today thousands of people come to undergo "speleotherapy" or salt therapy. Speleotherapy and the breathing in of salty air have been shown in clinical trials to have positive results, at least for children with bronchiolitis. Because the speleotherapy of the mine is such a big draw, and people stay in the mine for days or weeks at a time, numerous amenities have been set up here, such as a swimming pool, hot tubs, billiard tables, libraries, cafes, a restaurant, a wine gallery, salt spas, and an underground garden area for kids.
The mines even have several salt museums, with salt sculptures exhibited. And for those who want to go to church while 120 meters below the earth's surface, there's an Ecumenical Chapel carved from the salt.