With an elliptical shape, the field has a diameter of 1.2-1.4 km and a depth of 2,700 metres, with reserves of nearly 500 years, a real treasure for the Transylvanian economy. Massive salt exploitations left large subterranean gaps, where a salt microclimate with relatively constant temperatures, between 14-16 0C, low humidity 66-70% and higher pressure than the average surface of 735- 738 mmHg. Salina Praid Access to the salt mine is made by descending 300 steep steps, and a real underground town, at 120 metres deep, appears in front of your eyes. In the heart of the salt mountain, you reach the bus through a 1,500-meter-long tunnel, then access to the salt mine is descending 300 steep steps, and a real underground town 120 metres deep appears in front of your eyes. The air is highly ionized, highly effective in treating respiratory conditions. The treatments are done under the supervision of a medical team that supports the gymnastics and respiration programmes chosen for each individual disease. Practically, the treatment involves inhalation of air from the mine, and for good results, it takes about 18 days to spend at least 4 hours a day in the saline