Saunas first came into existence in Finland, around 2000 years ago. The tradition of the sauna has continued to this day. Currently, Finland has five million citizens, and more than two million saunas. That's an average of one sauna for every household. Saunas are considered a necessity in Finland, rather than the luxury they are seen as elsewhere in the world. There's even a sauna in the Finnish Parliament!

The traditional sauna is made of wood, and heated with rocks. Originally, Finnish sauna rocks were heated by wood fires. Then, later, the entire sauna became wood heated, first by an open fire inside the sauna, and then by metal wood stoves. Now, it's more likely for the sauna rocks to be heated electrically or by gas, though there are still traditional wood heated saunas. Modern sauna heaters allow the sauna to be ready faster, however.

Finnish saunas are around 175-200 degrees Fahrenheit. Water is thrown onto the stones that heat the sauna to produce steam, which makes the sauna feel even hotter than it already is. Periodically, people using the sauna may use birch boughs to beat themselves. This is intended to relax the muscles. As soon as the heat starts to become uncomfortable, one leaves the sauna, and traditionally jumps into a lake, the ocean, or a pool. If these are not available in the winter, Finnish sauna users may roll in the snow or swim in a hole that's been cut in the ice. Afterwards, one may return to the sauna, or sit down to enjoy food, usually sausage and beer.

It's considered rude to wear clothing while you sauna, although it's acceptable to sit on a towel. Mixed sex saunas are common, but Finnish saunas are considered entirely nonsexual. It would be very rude to make advances towards someone you see in the sauna. Although it's traditional to sauna in the nude, cooling off is usually done in a towel. It's very rude to wear a bathing suit in the sauna, because the chlorine from the suit could vaporize and be dangerous to people with breathing problems.

Foreigners in Finland may be surprised if they are invited into the sauna. This can happen while visiting, or after business negotiations. It's possible to refuse, but more polite to accept. Because of this, it's a good idea to be aware of the customs and methods of using the sauna in Finland. Offering a sauna is considered a sign of good hospitality.