Ocna Sibiului Resort

Ocna Sibiului is a town in Sibiu County, in the southern Transylvanian Plateau, north-west of the city of Sibiu, in the valley of the Vișa stream; it also administers the village of Topârcea. Beneath the town lies a salt massif whose dome forms an ellipse with axes of about 1.3 and 0.6 km. Salt was mined from Roman times, first at the surface in pits 12-15 m deep and later in bell-shaped underground mines; the last mine, St Ignatius, closed in 1931. The first spa resort was established here in 1845. The collapse and flooding of the old mines created the present lakes: Horea, Cloșca, Crișan, Pânzelor-Inului, the Bottomless Lake (Lacul fără fund), Avram Iancu, Ocnița, Sfântul Ioan, Poporului, Dulce, Brâncoveanu, Mâțelor, Vrăjitoarelor and Sfântul Ignat. Ten of them hold salt water, many with a concentration of about 260 g/l. Lake Avram Iancu, the former „Grosse Grube” (Great Mine), is 132.5 m deep and is considered the deepest man-made lake in the country. The Bottomless Lake, formed in 1775 when the Francisc mine collapsed, covers 0.2 ha, is about 34 m deep and is a geological nature reserve (Law 5/2000). The salt lakes are stratified: a layer of fresher water lies on the surface, while the salty layer below stores solar heat (heliothermy). In the Bottomless Lake, salinity rises from 96 g/l at the surface to 318 g/l at depth. The differences in temperature and salinity are used for therapeutic purposes, and salt-tolerant vegetation grows along the shores. Today the resort operates through the Ocna Sibiului Spa Complex, with two hotels, a restaurant, a treatment centre and an outdoor bathing area. The baths pavilion, built in 1907, is a class A historic monument (LMI code SB-II-m-A-12489). Bronze Age tools found in the town are on display at the Brukenthal Museum in Sibiu.