Research trip to Torhola

In June, the caving association did a combined research & training trip to Torhola cave in Lohja - Finland's largest limestone cave. The event was a in-cave training part of our basic caving course held by Ralf Strandell, the in-cave training was by Dare Talvitie, Jaakko Jääskeläinen and Jarmo Ruuth, with five trainees (youngest was three). Jari Arkko was testing a new spatial information application that pinpoints where the cave is underneath on the map when you walk in the environment. Jari and Taina Nyman also scanned Torhola's two side caves. We also observed flora and fauna in the cave.

That's a lot! Let's start unpacking the above with the new application. Jari had developed an application that can take as input cave coordinates, cave 3D models, and the orientation of those models with respect to the coordinate system. 

The application is used on the surface, and can then pinpoint in real time on a map display where the underlying caves passages are in relation to the user's position. This can be useful to understand where the cave is. It could reveal, for instance if there's any chance of finding additional entrances or points of the cave that are near the surface.

This is early work and needs further development. One of the issues observed during the test was the accuracy of GPS positions in phones. We observed +- 10 meter fluctuations, particularly in an area with foliage and cliffs. Similarly, the accuracy of the recorded cave coordinates and which part of the cave they point is an issue. There's also a need to obviously have either a 3D model or a plan view map to do this, and those need to be oriented in terms of their compass direction, altitude, and where on the map the published cave coordinates are.

Here's an example of using the system in its current state, with the blue dot showing where the user is and the black drawing indicating the outline of the cave underground.

Then to the training. This seemed to go very well, with some of the most eager cavers entering the lower tunnel from the basement of the Torhola cave from the outside. There's a rock blocking going to the actual cave, but we have not seen people go into this extremely small hole this far before. The hole is so small that only the people with thinnest bones can actually enter. Helmets, for instance, cannot be worn when entering, and even those who can enter need to twist and turn their body to go in. Well done!

What the small tunnel looks inside is shown in the opening picture of this article.

Here's a picture of what the entrance looks from outside:

Then to the scanning exercise. There are two side caves of the main Torhola cave, which we call Torhola 2 and Torhola 3. Their coordinates are N 60.252333 E 23.857586 and N 60.252292 E 23.857464, respectively. Torhola 2 is right behind the main cave and is small, the 3D model says 7 meters but some of that is probably not something a human can enter, the cave gets very low. Torhola 2 is larger and quite interesting to explore. The 3D model says 16 meters long, a dogleg shaped cave. The entrance is a crack that allows you to drop down to the cave.

Here is Taina scanning Torhola 2:

The Torhola 2 map can be seen in high-resolution here, the model downloaded here, and rotated in your browser here.

The Torhola 3 map can be seen in high-resolution here, the model downloaded here, and rotated in your browser here.

And here are the resulting 3D models and maps:

Finally, we looked especially carefully in Torhola 3 about if we can spot any living things or traces of them. The main occupants seemed to be spiders, of which there were plenty. The brave explorers in the lower tunnel of the main cave reported seeing many spiders there as well. 

In Torhola 3 there were also big roots growing through the floor of the cave and signs of organic material such as oak acorns/nuts.

Here are some pictures of the team looking Torhola 3, roots, and nuts, and spiderweb:

The cave is well marked, one of the most well-known caves in Finland. And a protected area. There's a parking lot with a sign pointing to the short trail leading to the cave:

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, Jarmo Ruuth, and Taina Nyman. All rights reserved.

Karkalinniemi cliffs & devil's churns

An evening. Not enough time to drive to any swimming place before they close, but maybe I could look up a nearby cave that I have not been to yet. How about in Pumminmäki, Lohja? This is on the famous Karkalinniemi (Karkali peninsula) that hosts also Finland's premier karst cave, the Torhola cave.

But this time we are not looking at karst or limestone, we're looking at ... gneiss? Hard rock in any case. And we are looking at a massive devil's churn. Or rather what's left of it, maybe 40%. This massive devil's churn was formed during the ice age when rapid water flows captured a rock to act like a drill that over a long period of time drilled a hole in the ground rock. Only for that ground rock to later crumble and have half of the cliff fall away.

Very interesting. Coordinates are N 60.283873 E 23.909360.

This has been listed in the book of Finnish caves as a cave, but it is a borderline case. There's clearly no darkness here, but there's a shelter from rain from the negatively leaning face of the churn. But it is also pretty high, so doesn't feel closed.

Still, interesting. And part of why I'm doing this is to go to different caves known in Finland, and check out what there actually is, take photos for the caving association's map and database, make a cave map if relevant. And often I find other things around the main target, such as additional small caves. See further down in the article.

Here's a 3D model about the devil's churn: downloadable model, model to rotate the place on your browser.

The model shows that the furthest point that's under the "roof" is about 6 meters from how far the roof extends to. Quite remarkable negative lean on the this thing! I don't have an exact number on how high the roof is but my sensor readings reach to 8.5 meters higher from the ground, but the roof goes further than that.

Retkipaikka has some more information about this place.

Photos:

But on the way here I noticed two shelter caves on an earlier part of the cliff. Nothing spectacular, also borderline cave or not, but wanted to record them in any case. The first one was maybe 9 meters long and perhaps 1-2 meters sheltered. The second one was right next to the first one, and maybe 11 meters long and maybe up to 3 meters sheltered.

Location of the first one was N 60.282078 E 23.910886.

Photos:

Location of the seance one was N 60.282183 E 23.910822.

Photos:

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.

Aulanko swim and (man-made) bear cave

Another after-work evening activity: visiting Aulanko's spa (hosted by the Scandic hotel Aulanko). This is a historic spa location, the old spa building is still there but today's spa visits are in the new fancy building. I had also heard about "bear cave" in the adjoining Aulanko nature park. 

The park is wonderful, and strolling around was amazing -- my first time there. I visited the rock tower, wonderful views of course, but also wonderful views from the viewing platform on the hill where the tower stands on. There's a high cliff dropping down from the hill and underneath the viewing platform, towards the lake Aulanko and the forests. Views really are stunning!

And then I descended the 330 steps down from the tower and the platform. Quite a walk, particularly when coming back :-)

Turns out the bear cave is not a natural cave, it is a wonderful sculpture in an excavated rock hole along the route down. It was crafted by sculptor Robert Stigell, and the rumor has it that he wanted a live bear cub from the Korkeasaari Zoo for his model, but when that turned impractical, he settled for a mounted bear cub instead.

On to the spa. I have been wanting to visit there for some time, but the facility has been under maintenance in April-May so could only do it now. 

The spa luxurious, it has a 25 meter swimming pool (just 2-3 lanes though), a half circle bigger warm pool with various water jets, a small outdoor pool, two cold plunge pools, a kiddie pool, and a bigger jacuzzi. The spa also favored by families, so be aware that there can be groups of kids in swimming school at the same time you are visiting, like in my case. Nice.

On the sauna side, there's plenty: the saunas differ between men's and women's sides, but on men's side there's a regular Finnish sauna, a steam sauna, and a "wilderness sauna". The wilderness is a fairly regular one, but just has wood/logs on the walls, and is darker. I think I've been to better wilderness or log saunas even in swimming halls, but it is really nice to have three different saunas. On the women's side there's a salt sauna.

The home page of the hotel & spa is here. You can visit the spa as a hotel guest, but also as a day visitor. Adult ticket to the spa as a day visitor costs between 19.50 to 28€ depending on day and time. Before 2pm on the weekdays it costs 19.50€, in the evenings 22€ and on Friday evenings and weekends 28€.

More information about the bear cave can be found here. It is in coordinates N 61.022598 E 24.470989.

Views:

Bear cave and walk down:

Spa photos below, starting with the old sauna building and then the new spa building:

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, 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. The pool photo in this article is from the spa's home page; all rights reserved by them.

The amazing Saariselkä!!

 

Now Saariselkä. This trip to the north is part of a week of staying at Tero's cottage in the wilderness and driving to different ski resorts. Now we are headed to Saariselkä. In many ways Saariselkä is the best or one of the best resorts in Finland. It is the most northern one not just in Finland but also in Finland. There's always winter. Skiers stop coming before the snow runs out. It is also not just on one mountain, but rather in a valley between two mountains which makes the scenery fun to look at, and of course also offers a choice of weather and snow conditions.

Very nice. 

There are some luxury cabins in Saariselkä, right on the mountain itself.

And a "Vohvelikahvila" (Waffle Cafe) at the snowy mountain...

More information about Saariselkä ski resort from their official website here.

Photos, first the slopes:

having a break:

A closed ski run. That is, a free of other skiers. Was nice:

Author:

Ski area map, showing the two mountains:

Sunrise on the way to Saariselkä:

Arrival:

Tero skiing:

Sun over our tracks:

This article has also been published at here. Read the full Planetskier series at planetskier.net, or all blog articles from Blogspot. Photos, videos, and text (c) 2021-2026 by Jari Arkko.