What is a Sauna?
It is a small room designed to be heated to very high temperatures, with well-controlled humidity. Saunas are used both for recreational and therapeutic purposes, with most people utilizing them as a relaxation tool that provides additional health benefits. The majority of saunas are built of wood, often aromatic, that release pleasing aromas as they heat.

There are two main types of saunas: dry and wet.
- Wet saunas are sometimes called steam rooms, and are kept at lower temperatures than their dry counterparts--usually between 100-115 Fahrenheit (37-46 Celsius). This, to prevent the superheated water from scalding the skin on contact.
- Dry saunas may be kept at much higher temperatures of up to 250 Fahrenheit (121 Celsius), by keeping the ambient moisture down to nearly zero.

Many cultures have independently created their own form of sauna. The Finnish sauna, which is by far the most popular globally, originated as a hole in the ground with a fire in the middle and an insulating roof. Many First Nations people of North America use a traditional sweat lodge sauna. These may be as simple as a hole dug in the ground, or as complex as an entire wooden long-house style structure. In most First Nations' saunas there is no internal fire; instead, stones are heated in a fire outside of the building and transported into the sweat lodge. Even many desert peoples have their own variants of the sauna, usually with full humidity and lower temperatures.

Saunas are thought by many to be best used alternating hot and cold. Many people enjoy leaving the sauna to leap into a body of very cold water. This shock is thought by some to be good for the immune system, though others hold it can be detrimental to one's health. Those with high blood pressure should be especially careful of this immediate transition from hot to cold, as it spikes blood pressure for brief periods.