A sauna (/ˈsɔːnə, ˈsnə/,[1][2] Finnish: [ˈsɑu̯nɑ]), or sudatory, is a small room or building designed as a place to experience dry or wet heat sessions, or an establishment with one or more of these facilities. The steam and high heat make the bathers perspire. A thermometer in a sauna is typically used to measure heat, a hygrometer can be used to measure levels of humidity or steam. Infrared therapy is often referred to as a type of sauna, but according to the Finnish sauna organisations, infrared is not a sauna.[3]

A modern Finnish sauna

Tampere, the third-largest city of Finland, has been officially declared the "Sauna Capital of the World".[4][5][6][7][8]