It is nature that brought renown to Gerolstein: the maar lakes, the Dolomites, and the Kyll river. Above are the castles; below, more than 250 meters (820 feet) underground, is a mineral spring. This spring is the source of the Gerolsteiner Brunnen company.
The mineral water bottled here first delighted the chemist Carl Fresenius back in the late 19th century with its high level of natural carbonation, and it still goes down well with German consumers today. According to a survey, no brand is sold more often than Gerolsteiner.