A canyon. A wonder of nature that I did not know existed in Finland. Amazing, truly amazing green views! A place so secret that I do not wish to even tell its name or coordinates, for fear of leading more traffic to this delicate natural place. The place is near Turku, however. Let's call the it "Kaarinan rotkoluola" (Kaarina crack cave). You may ask how we knew about this place. We had a friend with us with knowledge... so here we were.
More traffic in this place might also further disturb the neighbors who live nearby and seem unhappy about visitors. I get that, their houses are near. Let's all be careful, not spread the information unnecessarily. And if you do happen to visit this place, please please be quiet, stay out of sight, and don't park your car nearby or where it disturbs anyone.
The setting is a rocky hill or a cliff that is crossed by a crack. There is about 90 meters between the beginning and end of the crack, though it does not run exactly straight.
The canyon begins and ends as a crack, a narrow canyon that drops several meters into the granite hill. In both ends it starts mellow, just a meter or two first. But it goes further down and becomes narrower, eventually connecting above you.
There's two main sections in the cave. The first one is an (approximately) 12 meter path fully covered from above. Then there's a five meter opening in the crack above, But even in this section the canyon walls lean on one side by a half a meter or so, and one could perhaps argue that the cave continues here as well. At least if your definition of being in a cave is that you're protected from rain :-) From this point onwards the cave continues with another 11 meter path under the rocks.
Anyway, tentatively labelling the cave as having a length of 12 + 5 + 11 or 28 meters. That's respectable for Finland :-)
We were unable to go through the entire length at the bottom of the canyon. From the end of the crack you can come back, almost, to the place we had to climb up. But there's a very tight squeeze we did not feel like experimenting with... not sure this is doable.
Photos follow. This is what the canyon looks like from the top: