The oldest known sauna was made in Finland and were made from pits dug in a slope in the ground and primarily used in the winter. The sauna had features you would normally find in a traditional sauna such as a fireplace where stones were heated to a high temperature for the foundation of the heat, and water to throw on the hot stones to produce the steam that would create a sensation of increased heat. Doing this would make the sauna so hot and relaxing the bathers could take off their clothes and enjoy all the benefits the sauna had to offer. You can also imagine how relaxing it must have felt to be shivering in the cold snowy winter to then sitting back, clothes off in a steamy nice and hot sauna. These saunas are still alive today in places like Finland but are officially called "Smoke Saunas" or "Savusaunas", and they are made with logs almost looking like a cabin. Just take a look at the "Smoke Sauna" above.