Praid is a town in eastern Transylvania in Romania where the majority of the population is Hungarian. It was known from the seventeenth century as the Szelder (i.e. Hungarian) Salt Region. There are extensive deposits of salt which were exploited in Roman times and in the middle ages. Large-scale extraction began at Praid in 1762 when Transylvania formed part of the Habsburg Empire. It was supervised by the imperial mines officer Johann Frendl. In 1787 the mines became the property of the Habsburg government in Vienna. Extraction continued during the nineteenth century, but new technology employed from the late 1940s enabled production to be increased substantially. From the 1960s, following the example of the mine at Wieliczka in Poland, the therapeutic qualities of the atmosphere in the mine were recognised, and facilities were provided for people with respiratory conditions to spend several hours a day underground, during which they could take part in varied activities and if necessary receive treatment. The mine also contains a museum with multi-media displays and exhibitions of mining tools and other historic artefacts, together with a restaurant and wine-tasting facilities. Both patients and tourists access the mine on buses which travel 1250 m to ‘Level 50’, some 120 m from the surface, where the museum and medical facilities are located. Visitors can also see the chamber named after György Dózsa (1475-1514), the leader of a peasant revolt, and the even larger ‘Parallel Mine’, a chamber worked between 1864 and 1969 which is one of the largest in the world, some 100 m long, 40 m wide and 96 m high.