Erdsauna

The earth sauna is considered the most original form of the Finnish sauna as we know it today. Due to the low humidity, taking a sauna in this sauna is perceived as very pleasant, despite the high temperatures.
Originally, when building an earth sauna, a large and deep hole was dug into which a stone tub filled with water was let. A house was then built from pine wood, the roof of which was covered with twigs, moss and lichen.
Nowadays the earth sauna is usually built as an above-ground house made of pine wood. The center of the earth sauna is still a wood-fired stove. This creates a particularly cozy and rustic atmosphere.
The temperature here is 100 ° C and the humidity is 10-13%.

Hints:
No size and age restrictions
Image: Elypso