On my visits to Helsinki, I've followed a theme of eating in places favored by the late Marshal Mannerheim who was a keen culinarist and actually wrote a cookbook together with his sister.
So far I've been to Savoy, Bellevue and Seurahuone, which all seem amazingly well preserved with their pre WWII appearances. Also they all still seem to have some of Mannerheim's favorite dishes on the menu! At Bellevue, my waitress even noted that they were playing some of Mannerheim's favorite Russian songs as background music.
If someone knows of this famous person's other favorite eateries that are still well preserved, please let me know.