There are varying accounts of the sauna's origins, but the consensus is that it dates back to ancient Rome. To maintain their health, the Romans used charcoal and volcanic rocks to generate heat, a precursor to the modern sauna.
"Sauna" is a Finnish word originally meaning "a small wooden cabin without windows," a term likely related to the sauna's origins. The original cabins lacked windows and even chimneys, leaving the rooms stained black with smoke. Consequently, saunas were called "smoke saunas." Later, innovative individuals installed chimneys, giving the sauna a new look. However, "smoke saunas" still exist in some parts of Finland, but they are expensive and time-consuming to enjoy, as they require seven or eight hours of heating to achieve their full effect.