Sauna is originally used in Finland, about 2000 years ago. It had some similarities with the today sauna, but the main difference is that it was placed underground. The oldest writing in the world which is founded about saunas dates in the year 1112.
The modern sauna is a wooden room of relatively small dimensions, which offers an environment of strong and dry heat at a temperature of approximately 90˚C. In general, the lighting in a sauna room is dark. Heating is provided by a stove or heater that heats some volcanic stones to provide a gentle heat. This heat does not give much air to the sauna environment and therefore water is poured over the stones to increase the level of humidity. Treatment in the sauna is usually divided into sessions, the person passes a short time in the sauna until he starts sweating and then goes out to freshen up.