Top 4 Caves around Fröndenberg/Ruhr

It's slowly growing over, but you can still see the tunnel entrance. Actually a bit creepy. I'd love to know what this is....AI says "railway ventilation access", but is that so?

Medieval mining area in spectacular scenery, very well explained on the information boards along the way!

Great karst and mining landscape. Best viewed when the trees have little or no leaves.

The Caroliner Erbstollen in Holzwickede-Natorp is an important relic of early Ruhr mining. Its history begins in 1735 with the prospecting and subsequent excavation of the tunnel, the mouth of which is located on the Stuckenberg, about 200 meters east of the Natorper mill.  Originally, the tunnel was driven southwards as a crosscut and later mainly driven westwards in the side seam. On August 18, 1767, the tunnel received approval from the mining authorities to mine coal, and on October 2 of the same year it was granted the right to use the tunnel under the name “Carolien Erbstollen”.  Over the years, the tunnel was continuously expanded. In 1830, it reached a length of 3,913 meters and reached the boundary line to the Schwarze Adler mine in the area of the Cranefeld Siepen, today's Reuterstrasse. The tunnel was further advanced by the Schwarze Adler mine until 1843, so that the tunnel finally reached a total length of 5,184 meters, making it one of the longest tunnels in the Ruhr area.  Today, the entrance to the Caroliner tunnel is a visible testimony to mining history and part of the Holzwickede Historical Mining Trail. Visitors can gain an insight into the beginnings of coal mining in the region and understand the importance of the tunnel for the industrial development of the Ruhr area. 

With such a low and narrow tunnel, it must have been a very tough slog.

A lovingly designed memorial to the mining history of the 18th and 19th centuries.

In the extreme southeast of the GeoPark lies the Felsenmeer Hemer, a bizarre karst landscape that can be explored free of charge via a circular path with viewing platforms and panoramic bridges. Information boards provide the geological background.

The Felsenmeer in Hemer, a unique natural monument in the Sauerland, combines natural history and cultural aspects in a fascinating way. The geological formation of this remarkable geotope dates back millions of years and is the result of the weathering of limestone through dissolution processes. Rainwater, enriched with carbon dioxide from the atmosphere, turns into a weak acid that dissolves limestone, forming the characteristic rock formations of the Felsenmeer. Over geological periods, the impressive landforms that are now known as the Sea of ​​Rocks emerged. This nature reserve is not only a prime example of the dynamic forces of earth's history, but also a place full of legends. One of the stories is about dwarves who searched for precious metals under the rocks and about giants who wanted to steal these treasures. The legendary dwarven king Alberich is said to have used a magic spell to cause the ceiling of the rock hall to collapse, which buried the giants under the rocks and created the sea of ​​rocks. Visitors can explore the Sea of ​​Rocks on various paths, including a wooden walkway that leads directly over the cliffs and rocks. There is also a viewing platform and an upper bridge that are barrier-free, allowing visitors with limited mobility to enjoy the nature reserve. Dogs are allowed on a leash, and there is a large, free parking lot at the neighboring Sauerland Park. The Felsenmeer Hemer is a special experience in every season, be it snowy, in the colorful autumn forest or in the lush green of summer. The cliffs and caves of the Felsenmeer are part of the impressive karst landscape, which visitors can explore in more detail on display boards. The recognition as a "Significant Geological Monument of Germany" and as a "National Geotope" underlines the unique significance of this natural monument and its position as one of Germany's outstanding natural wonders.