Mario Botta (1943), an architect from Tessin, worked on this project for 15 years. The bathing complex Fortyseven along the banks of the Limmat River is 160 metres long and has eleven saunas and eight water pools.

Fourteen springs bubbling from the earth provide the water. The complex is not a water theme park. The beneficial and healing effect of the spring water is the primary focus. The name also refers to this use: the sulphur water from the springs has a maximum temperature of 47 °C.

Baden was already prominent in Roman times because of its thermal baths. The Roman name was, therefore, Aquae Helveticae, Helvetic waters. For this reason, the legionary camp Vindonissa (today’s Windisch) was established there. The Vindonissa Museum shows this history and the amphitheatre of Vindonissa.
Baden became the largest spa centre north of the Alps in the Middle Ages. After the Confederation (Eidgenossenschaft) occupied the Habsburg Aargau in 1415, Baden became the meeting place of the Confederation’s Tagsatzung (States General). The presence of the springs played an essential role in this decision.

Residenz and Brasserie Bad Schwanen
However, the great heyday was in the 19th century. Investors built huge hotels and spas along the Limmat. Some of them, such as the Verenahof, Ochsen, and Bären, still exist.
The Grand Hotel, three times as big (!) as the current new complex of 160 metres, was demolished in 1944. The casino, Kurtheater, Kurpark and Kursaal in the centre of the city are reminders of the grandeur of the Belle Époque.

After the First World War, the health resorts in Switzerland and Baden declined. The old Roman quarter on the Limmat, with splendid hotels and Spas, sank into a deep sleep.
The initiative of investors in 2006, combined with the architect’s creativity and craftsmanship, the involvement of Denkmalpflege and Heimatschutz, and the commitment of local authorities, companies, and citizens, has reawakened the Sleeping Beauty of Swiss spas.
Bathing in Open-Air Springs
On the banks of the Limmat River, the Bagni Populari Association (Verein) has revived the old tradition of hot springs accessible to all. Aquae Helveticae still seems to be an appropriate name.
On the other side of the recently opened Fortyseven bathing complex in Baden (Canton Aargau), another opening occurred in November, marking the revival of this two-thousand-year-old bathing culture.
The hot springs in Baden produce thousands of litres a day. In Roman times (15 B.C.- c. 400 A.D.), the numerous bathing houses (thermae) and springs were freely accessible to the inhabitants and soldiers from the nearby legionary camp of Vindonissa (today’s Windisch).
After the immigration/invasion of the Alemanni in the fifth century, the bathing culture disappeared. However, in the fourteenth and fifteenth centuries, Baden again became the most important bathing resort in Central Europe.

However, there is one notable difference with Roman times: the aristocracy and bourgeoisie had their own bathing houses. Ordinary people used the many hot springs in the open air. This tradition continued until 1870.

In this period, the large bathhouses and spas for the Beau Monde were built in the city’s bathing district (the Roman quarter). This clientele shouldn’t be confronted with poor people bathing in the open air on their way to their destination. The open-air baths disappeared, and a ban was even in force until recently.
The association Bagni populari, founded in 2017, has taken the initiative to reopen these springs (between 37 and 43 degrees Celsius, depending on the outside temperature) to the public. After all, the springs still exist, and they otherwise go straight into the Limmat.


And an artificial hot open air spring in Basel (15 December 2025)!