If you live in Helsinki or visit there and you haven't visited the Postal Museum in the basement of the old Post Office next to the train station, you might want to consider it.
It begins with a collection of postal swords (easy not to notice until you're on your way back out) and postal uniforms going all the way back to the 1600's. Did you know the sackcloth peasant delivering mail back then actually had a badge on his sackcloth? There are numerous galleries and it is easy to miss half of them if you don't notice the dogleg that leads up steps or a ramp (can't remember) to that half of the floor. There are at least three short films of 5-9 minutes and probably more like 6-7 shorts. Each can be narrated in Finnish, Swedish, or English. We watched the film on postal railroad cars but not the one on the old postal buses or any of the others. There are a variety of styles of exhibit aimed at people with different interests. I remember some mailed bundles that are sawed in half so you can see what kinds of food people used to mail and how they wrapped it. There's a lot of postal paraphenalia, there's a gallery of old letters, and other types of exhibits. There is likely to be something there to surprise you. Postal history and postal technology are a lot less likely to attract visitors than, say, a museum of art or natural history. But I have to say that considering the subject material they had to work with, this is a nicely done little museum that was interesting to visit.
Admission is 6 Euros for adults, 3 for children. You might accomplish the whirlwind version in 30 minutes if you don't start read many texts or watch more than maybe one short film. At the most, I have trouble imagining that you could spend more than 3-4 hours if you watched all the shorts, read all the texts, and tried to decipher some of the envelopes and letters in the old-letter gallery.
Don't take any of the free post cards. There is what looks like a temporary gallery of free post cards. At the top of the racks almost all of them say "free post cards." There are only two things to tip you off that these are valuable artifacts on exhibit and not actually free postcards. One is that there only one of each item and it's the only one in its slot. The other is a sign on a table saying in Finnish (maybe English also, I don't recall) "Please don't take the postcards. They are exhibit material."
Helsinki Postal Museum
Helsinki Postal Museum
As he persisted, I was obliged to tootle him gently at first and then, seeing no improvement, to trumpet him vigorously with my horn.