Pfaffenberg · Wiehl · Oberbergisches Land

A reef from the Devonian sea, 30 metres beneath the forest.

Around 390 million years ago a warm sea lay here. Today 26 steps lead down into the limestone it left behind – and to dripstones that grow about one centimetre in a hundred years.

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11:00
12:00
13:00
14:00
15:00
16:00

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Duration: 45 min
In the cave: 8 °C
Tours: 10 am–4 pm
Adults: €6.50

Stairs with a handrail lead between rock walls into the dripstone cave — **The descent**26 steps · 7 m below the forest floor

The way down

From the forest floor to 30 metres deep

The tour is a cross-section through Earth’s history: forest and loam on top, then slate and sandstone, then the limestone of an ancient reef. Over a very long time, water dissolved passages and halls in it.

0 m · Ticket office at the forest edge
Meeting point in the beech wood
Tickets and meeting point at the kiosk. The tour starts on the hour.
7 m · after 26 steps
The stairs into the limestone
After 26 steps the forest floor is 7 metres above you. The air turns cool and damp.
30 m · deepest point
In the middle of the reef
At the very bottom you stand in Devonian limestone. It is around 8 °C here all year round – in high summer and in winter.

Weathered loam Clay slate and sandstone Devonian reef limestone (limestone pattern) Tour route

Diagram: the depths 0, 7 and 30 m come from the tour; layer thicknesses and the course of the passages are simplified. Geology after the Geological Survey of NRW (geotope GK-5011-002).

Earth science in 45 minutes

How a drop becomes a dripstone

Every drop that falls from the ceiling carries a little dissolved lime. Some of it stays behind. That is all – just very, very often.

CaCO₃ + H₂O + CO₂ ⇌ Ca(HCO₃)₂Limestone + water + carbon dioxide ⇌ dissolved lime. To the right the water dissolves the rock, to the left it deposits it again as dripstone.

This is roughly how much a dripstone here has grown since the first tour in 1927. Please do not touch – skin oil stops growth at that spot.

Rain turns acidic
In the forest soil, rainwater takes up carbon dioxide and becomes weak carbonic acid.
The acid dissolves the limestone
In fine fissures the water dissolves the limestone. Over a very long time, passages and halls form.
The drop gives the lime back
In the cave air the carbon dioxide escapes. The lime is deposited – a stalactite grows above, a stalagmite below.

Close-up of the flowstone surface in the dripstone cave

Timeline

390 million years, four moments

390 million years
In the Middle Devonian the Bergisches Land lies beneath a warm sea. Corals build a reef – the later limestone.
Timeline broken
around 1860
Blasting in the quarry on the Pfaffenberg opens up cavities.
4 Aug 1927
The first public tour begins.
2027
100 years as a show cave. The anniversary programme follows.

Low chamber with lights in the dripstone cave

Experience

More than a guided tour

News

Latest from the cave

15 October 2026
Easter egg hunt in the cave
Hunting for Easter eggs 30 metres underground: an Easter egg hunt in the cave is being planned.
15 October 2026
Christmas party in the cave
The cave takes a break in winter. For Christmas parties, special occasions and groups we open on request.
12 October 2026
Halloween in the dripstone cave
Projector and holograms turn the tour into a spooky adventure – from 17 October 2026.