A room or separate building with wooden floor and walls and a stove that heats all this goodness. The temperature is regulated by the water that hits the stones. The steam is called "löyly" and is considered the spirit of the steam room. Most houses have their own sauna. And if at the mention of Russian banya in another head can arise vulgar thoughts, in Finland sauna is equated almost to the church.
To receive an invitation to a sauna is a real honor, it means that the interlocutor wants to get to know you better. Especially since a naked person has nothing to hide. Do not count on aromas, fancy lighting and exciting music, in Finnish sauna everything is simple and classic: dim light, the smell of wood and tar, silence or unhurried quiet conversation.
You can enter the steam room in a towel, but inside everyone sits without anything. This is the case when people of the same sex gather in the room - there may be a compartment for both sexes. If you are not ready to look at other people's charms and show your own - you can put on a towel. Go into the steam room, sit there not to the point of fainting, get into a cold pool or jump into the snow (reminds you of something, doesn't it).
In Finland they also have birch brooms - vasta and vihta - which you can use to spank yourself, if you don't feel sorry for yourself, or your neighbor. And do not hesitate to pour hot water on the stones - an extra portion of steam has never killed anyone. Moreover, it is customary for the person entering to give steam.
To avoid dehydration, drink more water or Finnish blueberry juice.
The most famous saunas in Helsinki: Kotiharjun, a modern Löyly with access to the waterfront; and SkySauna, where you can steam in a cabin on the Ferris wheel.