The Headquarters Museum occupies the building on Päämajankuja where Marshal Mannerheim commanded the Finnish Armed Forces during the Winter War (1939–40) and the Continuation War (1941–44). This was the nerve centre of Finland's military resistance, and the museum preserves it in remarkable detail. Mannerheim's office, the conference rooms, and the communications centre are all on display, with extensive documentation of both conflicts.
The museum is small but dense with material. Maps, orders, and personal correspondence fill the cases; audiovisual exhibits explain the strategic situation Finland faced. Understanding the Finnish defensive posture — a country of four million against the Soviet Union — gives the displays an emotional weight that standard military history sometimes lacks. Staff can provide context in English. The museum is open year-round; check the website for seasonal hours.