Târgu Ocna is a town in Bacău County, Romania, situated on the left bank of the Trotuş River, an affluent of the Siret, and on a branch railway which crosses the Ghimeş Pass from Moldavia into Transylvania. Târgu Ocna is built among the Carpathian Mountains on bare hills formed of rock salt. Târgu Ocna's main industry is salt production, as it is the largest provider in Moldavia. Other industries include wood processing, coal mining, steel producing, and petroleum-based industries.
Diversity of tourism resources available to Târgu Ocna determine the possibility to practice various forms of travel, as: the Spa tourism is favored by the existence of natural factors of course, to base treatment of Măgura Spa Complex and facilities for treatment made by the company Târgu Ocna Salt Mine at underground level IX;
The natural Spa, by mineral water springs (sulfur, chloride, sodium, low bicarbonate, hypotonic, recommended for treatment of diseases of the digestive tract, hepato-biliary, gynecological, chronic rheumatic and respiratory tract); Saline environment (Salina Târgu Ocna), whose microclimate is recommended to treat chronic respiratory diseases (mainly asthma, chronic bronchitis); sedative bioclimate, of mercy, with light shades of stimulation.
On the Măgura Hill slope occur along a line seven mineral springs, whose catchments were furnished and used for over 100 years (1888). The kiosks are made of wood, and the mineral water flows free through plastic pipes in buvetes. Along are shown in the mineralogical composition of water and therapeutic recommendations. Analysis conducted by the National Institute of Recovery, Physical Medicine and Balneoclimatology - showed that the mineral content between 4.139 - 12.793 g/l is relevant for therapeutic internal and external cure.
Troilus Salt Mine is a working mine where the salt is still being extracted by machine and manually. The mine area used as the sanatorium is 240 m from the surface, at the ninth level and is reached by a tunnel 1.75 km long and wide enough in places for two coaches to pass each other. Over 5000 people were treated in this mine last year alone. The reasons given for the improved health, rise in immunity and cures in some cases of patients, is that the air contains no allergens, the temperature and humidity is constant, but the most important factor is that the salt gives off negative ions.
In the heart of the salt mountain there is “Saint Varvara” Church, considered to be the spiritual patron and protector of miners, and every first Saturday of December is the celebration of the church patron.
Here you can find a 3D panorama of this (only, it seems) orthodox church built in a salt mine.