Nearly 13,000 years ago, clouds of hot volcanic ash from the Laacher See (Lake Laach) Volcano raced down the Brohltal (Brohl Valley) and filled it with huge amounts of loose volcanic material. Even today we can see traces of this impressive spectacle: Follow the road to the right beyond the complex of buildings and walk a few metres uphill. On the slope to the right, the layers of ash (trass), which settled on the older underlying massif, are clearly visible.
Where there has been volcanic activity, mineral springs are rarely far away. At the nearby baroque fountain temple of the Bad Tönisstein mineral springs you can quench your thirst with water from deep underground.