They are known as the "Baths of Bormio" but they are actually found on the territory of the Comune of Valdidentro; it is certain that the therapeutic properties of the thermal waters of the Baths were already known in the pre-roman period: Pliniana Source, Cassiodora Source, Bagni Romani (Roman Baths) are toponyms that however show the interest that the scholars of ancient times may have had in these hot water that gush out of the living rock at a constant temperature of over 40° degrees. Many hospices started to appear in proximity of the sources both for those seeking cures and for travellers who needed shelter before facing the long climb towards the Umbrail Pass and the Engadine
along the valley leading to the Stelvio Pass, today it is the highest carriage road in Europe.
St. Martin Church, which still stands near the Bagni Vecchi of Bormio (Old Baths), was actually built before the 13th century, it is unspoken evidence of the evolution regarding the story of Alta Valtellina. The Bagni Vecchi of Bormio were later converted into lodgings for very important visitors who came to Alta Valtellina. In 1493 one such visitor was Leonardo da Vinci "At the top end of Valtellina there is the mountain of Bormi, always incredibly covered in snow. There are ermines; In Bormi there are the Baths". In 1496 Lodovico il Moro was a guest at the Baths of Bormio.
The Baths were not used for tourism until 1823 when the Stelvio road was made by the Austro-Hungarian Empire to connect the Lombardy Region with Tyrol. It was during this period that the still standing hotel services were later increased. Thermal treatments and mud-baths first started to appear on the advertisment posters of the Baths in the 19th century.
From May to October very important families came to the Baths, some families even came from over the Alps. The singularity of these Baths is the natural "sweating Grotto"; It penetrates into the living rock for more than 50 metres, passing through "Paradiso" (Paradise), "Purgatorio" (Purgatory) and Inferno. According to the degree of heat and steam, the temperature keeps increasing to the end of the grotto. At this point a steaming cascade of thermal water gushes from the rock at over 50°C. The Sweating Grotto: it is the most fascinating and healthy natural sauna in the World.
