I thought it was a joke when I heard about it a couple of years ago, but Finnish tango is a real thing.
So is German-language-loving dirty ol' Finnish men, apparently. Sheesh.
Tango came to Helsinki as early as the 1910s, and was at the height of its popularity in the 1950s and early 1960s, when songs like "Satumaa" by Reijo Taipale's "Satumaa" caught on as indigenous popular music:
Want to learn more? Go here and here. The New York Times recently ran a story about Finnish tango as a dying art; read it here.