Blue Lake, Baia Sprie

The Blue Lake lies on Dealul Minei, in the north-western part of the town of Baia Sprie, at the foot of the Gutâi Mountains and at an altitude of 530 m, close to the DN18 road between Baia Mare and Sighetu Marmației. It is a protected area of national interest, in IUCN category III (hydro-geological nature reserve), designated by Law no. 5 of 6 March 2000, covering 0.50 hectares. The local press also mentions an earlier designation as a nature reserve by local council decision no. 204 of 16 March 1977. The lake formed in 1919-1920, when old mine workings on the Domnișoara vein collapsed, and rainwater seeping into the old excavation collected in the resulting hollow. It is elliptical in shape and up to 4 m deep. According to Wikipedia, the water contains iron sulphate and melanterite from the old mine, is highly acidic and has a blue-green colour. The colour changes with the season, the water temperature and the position of the sun: light or dark blue in spring, dark green in summer, and dark green to brown in autumn. The lake is surrounded by sessile oak and pine forest. According to the local press, the lake is reached on foot by a path marked with a blue dot that starts behind the Roman Catholic church in Baia Sprie: about 20-30 minutes through the old miners' quarter, then about 20 minutes through the forest on built steps. Since 2025 Dealul Minei has also been home to the Mines Park, with marked mining-themed trails.