Saint Ana Lake Natural Reservation
“Saint Ana” is Romania’s only volcanic lake. It lies in the Harghitei Mountains, on the left bank of the Olt River near Tuşnad. At 946 m, the lake occupies the bottom of an extinct volcano, named Ciomatu, from the volcanic massif Puciosu, whose 1,301m summit was the location of the most recent volcanic eruption in the Carpathians, and indeed Central Europe, several thousand years ago. Almost circular, it is 620m long and 460m wide at its widest point, has a surface of 0.2 km2 and a maximum depth of 7m. The lake draws its water exclusively from rainfall and snowmelt, it doesn’t have any other inflows.Its water’s purity comes close to that of distilled water, containing only 0.0029ml minerals per litre. Extremely poor in oxygen, the lake supports no animal life.
A reserve on account of its natural, geological, floral and wildlife riches, Sfânta Ana Lake is linked to Băile Tuşnad resort by tourist paths and a road.