Sauna

Saunas are present in every village, save those built with kotas. They are small (usually no bigger than 2x3) buildings, and always include a fireplace, a table, a sauna scoop and a wooden tub. One part of the Advanced adventures course needs you to use a sauna. To do so, remove all your clothing, then with a container of water in your inventory, [a]pply the sauna scoop.

It is possible to build a sauna in your home by stealing a tub and scoop from a village.

Saunas make good player homes. All that is needed is to block up the entrance with a fence, so that only the player has access inside.* Saunas can also function as smokehouses.


 * Seems to not work anymore, NPC's climb over the fence: