Perhaps the most traditional sauna in existence. In the Finnish sauna you can enjoy yourself just as the Finns did a thousand years ago. They heated their (cave) dwellings with stones heated in fire. It was discovered by chance that when water was poured over the hot stones, the steam that was released provided extra heat.
The principle of the Finnish sauna is essentially still the same as before. Water is poured over the stones heated on a stove. The room has a temperature of 90°C and a humidity of 30%.