Mikaelshulen

Mikaelshulen is a well-visited cave on the shorelines of lake Norsjø near the town of Skien. Skien is about 2.5 hour drive southwest from Oslo. The cave has acted as a catholic church, dating back to 1300s, and was also an important place of pilgrimage. It isn't large -- 25 meters by my measurements -- but is definitely awe-inspiring with its location on a cliff, overseeing a lake, and sun shining directly into the cave. Today it is a popular hiking destination.

According to references, "Church in Mikjálsbergi" was listed in year 13987 in a bishop's land ownership book as an owner of land in the area. The cave was named after Archangel Michael in Catholic times, some time before the Reformation 1536-1537. From the Reformation until 1843, the church was a refuge for remaining Catholics. Practicing Catholic faith was a serious crime after Reformation. 

A description from 1643 calls the cave "Templum Mirabile" (wondrous temple). 

Above the cave, at the top of a mountain there is also an ancient burial ground site. I didn't go see the burial ground, but read somewhere that the site hasn't been visible for a long time.

There are many St. Michael's churches in Norway, some of them in caves as the Archangel was often depicted fighting serpents or dragons.

But back to Mikaelshulen. This cave was formed when weaker rock weathered away, also helped by sea waves and ice when the cave was at sea level in the post ice age period. The cave may also have seen modifications or enlargements by humans; there aren't any obvious structures but of course additional rock might have been chipped away. In today's state the cave also has some graffit.

The cave is reachable on foot, or by boat, and is a popular hiking and tourist attraction. Boats can arrive on the pier built by the lakefront, close to the cave.

The cave is in the middle of a massive cliff ending right at the lake, today at an altitude of 30 meters above the lake. There is a well-prepared trail to the cave, but it does involve first some stairs. And then just before the cave you'll need to do some climbing on a steep rock face, helped though by metal handrails:

I scanned the cave with my iPhone's lidar sensor, and then processed it to get a plan view and some vertical cuts of the cave shape. The 3D model can be downloaded here, or rotated on your browser screen here. The full PDF map is accessible here. Below are some sample photos of the model and the map, however.

According to my model, the cave is roughly 25 meters from the drip line to the end. Other sources list the length usually at 20 meters, though. Not sure if my iPhone lidar is inaccurate.

Other articles about this include Wikipedia, Velma Aho's blog post, ut.no article, cultural memory search site entry, skiensatlas page, showcaves.com entry, visitnorway page, and visittelemark page.

There's a parking lot to get to the cave at . There's a well-prepared trail, one way length is about 1.7 km. The trail vertical gain is around 100 meters. Here's the trail map:

More pictures of the cave:

Climbing:

View from the top of the trail to the lakes:

Signs on the road:

This article has also been published at Planetcaver.net here. Read the full Planetskier series at planetskier.net, urban exploration stories from theurbanexplorer.net, and other underground stories from planetcaver.net, or all blog articles from Blogspot. Photos and text (c) 2026 by Jari Arkko. All rights reserved. The drone picture showing the cliff from above the lake is from ut.no article by Skien-turlag.

The Swim-Every-Day Challenge

It is good to swim... maybe even every day. In August I had a very nice swim above the rooftops of Stockholm, and decided that I'd try to keep up swimming every day, for as long as possible. It continued through my time at home, on my health rehab in Punkaharju, across business trips to Zürich and Riga, and for the last few days at my summer cottage and once near my office. Sometimes challenging to find the time before swimming pools close, sometimes cold in the September lake waters, but always special. Glad I'm doing this!

By now I've swam on 35 days consecutively. But it will probably fail in the coming weeks, too much travel and work and other things to make it possible to find a place every day. And the outdoor swims get too cold. But let's see.

Overall it has been an excellent experience. Every day nice views, every day a refreshing dip, sometimes borderline cold dip :-) And there's been a reason to get out and walk or drive to a different place.

Out of the 35 places, I swam at my cottage beach three times, visited my home town swimming pool twice, used a nice hotel pool twice in Riga, but also swam in 22 new places. Most of the new places were beaches either near my work place that I had not been to, or beaches alongside my route to Punkaharju. Some were swimming pool or  spas where I travelled to, a couple were beaches there.

I particularly want to highlight Störsvik (Siuntio), Sandviken (Inkoo), and Sandfjärden (also in Inkoo). These are 20-30 minutes away from my work places, and about an hour from Helsinki center to the west. But they are wonderful, sandy places, Störsvik is a blissful sandpit with very clear and warm waters. Sandviken is a secluded sand beach on the seafront far away from people, and Sandfjärden is an easily accessible another sand beach by the sea.

Sometimes the swims were long, 400 to 900 meters. At other times very short, from a half a meter quick swim in cold water :-) to few meters... September in Finland can be cold. And at other times somewhere in between. And once I run out of time so had to fill up the jacuzzi in my basement and attempt to "swim" in it.

Here's the full list of my swims so far:

1. Aug 18 - Selma City Spa, Stockholm, Sweden (see the opening picture above, photo below, or the article, alt. link)

2. Aug 19 - Keski-Espoo swimming hall, Espoo, Finland (no article but pictures below)

3. Aug 20 - Kasnäs spa, Kasnäs, Finland (article, alt. link)

4. Aug 21 - Laukkoski school beach, Laukkoski, Pornainen, Finland (article, alt. link)

5. Aug 22 - Galträsk, Kauniainen, Finland (no article but pictures below)

6. Aug 23 - Kruunupuisto beach, Punkaharju, Finland (article, alt. link)

7. Aug 24 - Kruunupuisto spa, Punkaharju, Finland (no article but pictures below)

8. Aug 25 - Kruunupuisto spa and then later the Kruunupuisto sauna and beach, Punkaharju, Finland (article, alt. link)

9. Aug 26 - Karjalankallio lean-to, Punkaharju, Finland (article, alt. link)

10. Aug 27 - Punkaharju public beach, Punkaharju, Finland (article, alt. link)

11. Aug 28 - Naisvuori swimming hall, Mikkeli, Finland (article, alt. link)

12. Aug 29 - Sinilähde beach, Heinola, Finland (article, alt. link)

13. Aug 30 - Kauniainen swimming hall, Kauniainen, Finland (no article but pictures below)

14. Aug 31 - My basement jacuzzi, Kauniainen, Finland (article, alt. link)

15. Sep 01 - Störsvik sandpit beach, Siuntio, Finland (article, alt. link)

16. Sep 02 - Sandviken beach, Kopparnäs, Inkoo, Finland (article, alt. link)

17. Sep 03 - Sandfjärden beach, Kopparnäs, Inkoo, Finland (article, alt. link)

18. Sep 04 - Kauniainen swimming hall, Kauniainen, Finland (no article but pictures below)

19. Sep 05 - Paavolan salmen uimaranta, Lohjansaari, Lohja, Finland (article, alt. link)

20. Sep 06 - Vilniemen uimaranta, Espoo, Finland (article, alt. link)

21. Sep 07 - Freizeit Bad Opfikon, Zurich, Switzerland (article, alt. link)

22. Sep 08 - Freizeit Bad Opfikon, Zurich, Switzerland (article link above, went twice)

23. Sep 09 - Hallenbad City, Zurich, Switzerland (article, alt. link)

24. Sep 10 - Kylmälä, Kirkkonummi, Finland (article, alt. link)

25. Sep 11 - Laaksolahden uimaranta, Laaksolahti, Espoo, Finland (article, alt. link)

26. Sep 12 - Plaža Kašjuni, Split, Croatia (article, alt. link)

27. Sep 13 - Beach Divulje, Kaštel Štafilić, Croatia (article, alt. link)

28. Sep 14 - Radisson BLU Latvia Conference & Spa, Riga, Latvia (article, alt. link)

29. Sep 15 - Welton SPA Centrum, Riga, Latvia (article, alt. link)

30. Sep 16 - Radisson BLU Latvija Conference & Spa, Riga, Latvia (went twice; see article link above)

31. Sep 17 - Welton SPA Riverside, Riga, Latvia (article, alt. link)

32. Sep 18 - My summer cottage, Teisko, Finland (no article but pictures below)

33. Sep 20 - Still at my summer cottage (no article but pictures below)

34. Sep 20 - Still at my summer cottage (several days here, again no article but pictures below as well as at the top of this article)

35. Sep 21 - Långvik beach, Kirkkonummi, Finland (no article but a picture below)

This article has also been published at Planetswimmer.com here. Read the full series of sauna and swimming stories from planetswimmer.com and saunablogger.cool, or all blog articles from Blogspot. Photos and text (c) 2026 by Jari Arkko. All rights reserved.