What is a smoke sauna?

A smoke sauna is the dry, wood-fired version of a sauna. The fire is lit in mid-afternoon and when the wood has burned down the doors are opened to release the smoke and the sauna is ready for action.

The Finns especially hold the tradition in high esteem.

They will sometimes use the word "smooth" to differentiate the heat of the smoke sauna from the more abrupt heat of the electric model. The rich, tarry smell is supposedly therapeutic, another tick for the smoke sauna.

When things really get steamy in the sauna, the Finns lash one another with birch branches, supposedly rejuvenating for the skin.

The smoke sauna also has a tendency to spontaneously combust. After several years, the dry wood and intense heat prove a fatal combination.

Ideally the smoke sauna is sited beside a lake. Those inside will periodically emerge and plunge into the icy water to jolt the circulatory system into full heart-pumping action.

In my one smoke sauna experience, a fellow perspiree had served as part of the UN peace-keeping force in Sinai. "The temperature was incredible. Fifty degrees sometimes," he told me.

And what was the first thing these Finnish soldiers built? A smoke sauna, naturally.