Lacul Sfanta Ana

Lacul Sfânta Ana is the only volcanic lake in Romania, located at the bottom of the crater of an extinct volcano — Ciomatu Mare — within the Ciomatu (Ciomad) massif, in Harghita County, on the left bank of the Olt river, near the resort of Băile Tușnad. Situated at an altitude of approximately 946 metres, the lake has a distinctive shape, a diameter of around 1,700 metres and a maximum depth of approximately 7 metres. The crater in which it lies is the result of the most recent volcanic eruption in the Carpathians and in Eastern Europe, estimated to have occurred several tens of thousands of years ago. One fascinating characteristic of the lake is that it has no springs: its water comes exclusively from precipitation — rain and snowmelt — which gives it a remarkable purity approaching that of distilled water, and a scarcity of nutrients that limits aquatic life. The highly ionised air and the landscape of the crater, surrounded by steep walls and forests of beech and spruce, create a distinctive atmosphere, which is why the site is considered one of the most beautiful natural treasures in Romania. Lacul Sfânta Ana forms part of a nature reserve that also includes Tinovul Mohoș, located in the twin crater, separated only by a narrow ridge. Mohoșul is a unique peat bog — a former volcanic lake transformed into a sphagnum moss wetland with a thick layer of peat reaching up to 10 metres — sheltering relict plants from the glacial era and carnivorous species such as sundew. Due to the fragility of the ecosystem, the bog can only be visited along specially constructed wooden walkways. The Lacul Sfânta Ana – Tinovul Mohoș ensemble represents a geological and botanical site of national and European significance, considered by specialists to be unique in the world for its scientific value.