Munterley, Dolomite rock formation in Gerolstein, Germany.

Munterley is a dolomite rock formation rising steeply from the Kyll Valley floor with nearly vertical stone walls. The outcropping forms part of the Gerolstein Dolomites cluster, a series of similar limestone peaks scattered across the valley landscape.

This limestone formation developed roughly 380 million years ago during the Devonian period when the region was a shallow subtropical sea near the equator. The rock accumulated as marine organisms built reef structures in warm water over long periods of time.

The name Munterley comes from the local dialect; the steep rock face is still used by climbers today. On the northwest side, the Buchenloch, a 36-metre-long karst cave, was inhabited in the Palaeolithic. Celts and Romans later settled around the rock and drew inspiration here for building temples and shrines.

Several hiking trails provide access to and around the rock formation, connecting to a marked circular route through the Gerolstein Dolomites area. The paths are open to walkers of different abilities, though sturdy footwear helps with uneven ground and slopes encountered along the way.

The dolomitisation that turned the Devonian reef into rock destroyed its fossils: the calcium carbonate of the coral and stromatoporid skeletons was leached out and replaced by magnesium carbonate, so no fossils remain in the walls. The 36-metre Buchenloch cave on the northwest side, once inhabited in the Palaeolithic, is the detail to look for.