In Antti-Jussi Annila's historical horror film, Sauna (Finland 2008), set at the end of the sixteenth century on the border between Russia and Finland (then Sweden), a professional Finnish soldier named Eerik and his younger brother Knut participate in a border commission. This commission's task is to establish a new border between the Russian and Swedish empires following the conclusion of a peace treaty after the Russo-Swedish War. Early on in the film, Eerik brutally kills a man (who offered him hospitality) for hiding Russian icons, after which the brothers lock the man's daughter in a dark cellar, leaving her to die. This gruesome act haunts Knut for the rest of their journey. The Russian–Swedish border commission arrives at a marshy area in the woods, inhabited by mysterious people who fear a rectangular concrete hut – resembling a hut in the style of modern construction, rather than being historically accurate – standing in the middle of a swamp, which they call ‘the sauna’. After a number of strange occurrences, neither the Russians nor the Finns/Swedes want to include the marshy area within their borders. Meanwhile, Knut becomes obsessed with the sauna, and when he finally enters its pitch-black interior, the ghost of the girl who was left in the cellar appears before him. After this, Knut transforms into the ‘agent’ of the sauna, due to whom all the members of the border commission eventually lose their lives, including Eerik, who in his last moments confronts his darkest sins and fears inside the sauna. As a result, the border agreement is never brought to fruition.

In the film, the sauna is a multi-layered symbolic space that performs several plot-related functions. First, it refers, at least by name, to the traditional Finnish bathhouse and can thus be seen as an incarnation of Finnish national space. At the same time, it is a space where the protagonists’ darkest feelings surface, especially guilt, while also serving as an imaginary screen that reflects society, primarily by exposing ‘the lives lost in the construction of national community and the imposition of human-made structures on the natural world’ (Kääpä 2014: loc. 1656). The sauna also impedes the final establishment of the border, thwarting human actions and plans.