The hot mineral water aquifer flows from the Upper Devonian limestones that meet the Variscan thrust front of the Rhenish Massif,[1] and flow through the city center of Aachen in a 500m long by 50m (maximum width), that emerges from the source at numerous spring heads.

The hot springs have been used for balneotheraputic purposes since the early Roman settlement in Aachen.

The historical political and economic growth of Aachen developed around the springs, in particular mineral water production, the spa and bathing sector, and the textile industry.

Around 600 BC, the Celts arrived; later in the 1st century AD, the Romans established a large spa for the military at Aachen.

[4] The hot mineral water emerges from the source at an average of 158°F / 70°C,[5] and is high in sodium, chloride, and sulfate.