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Porvoo Finland is the second oldest city in Finland. Its main attraction is an old town of original houses and buildings built in the 19th century that remains largely unchanged by time.
I have read that it can be quite crowded here in the summer, but when we visited at the beginning of September, we felt like we had the place almost to ourselves. The Porvoo Tourist folks have put together a great book with information about the old town and a helpful and informative walking tour to see it.
Porvoo is an easy one hour trip from Helsinki by bus, making this a great way to get out into the countryside and see a little more of what Finland has to offer!