The water rises to the surface from a depth of 2,000 meters in the city centre in the Saalgasse and Langgasse area. The springs are estimated to be at least 200,000 years old. This gift of nature not only has beneficial effects when bathing, inhaling or drinking. The stored heat can also be used to heat homes and buildings. Wiesbaden's thermal water is therefore a regenerative energy source that is virtually inexhaustible and unique in Europe in this form.