Helsinki

Suomenlinna, the island fortress that formerly guarded the harbor, for one. The harbor market for some intersting food. If you like big cats, the zoo (located on an island) has a pretty nice menagerie. The National Museum- surprised me, because it nicely maps out how Finland went from being one of the least developed countries in Europe to one of the richest in barely 150 years. The outdoor folk museum wasn't the best of these sort of parks I've seen in Europe (that would be Belgium's Bokrijk), but worth a look if you have time and the weather holds up. The main Cathedral is iconic, but kind of spartan on the inside.

Temppeliaukio Kirkko.

The Rock Church.The Esplanade, Sibelaeus Park & Museum. The White Church.

I would spend one day doing Rick Steves' walking tour and shopping and one day going to Suomenlinna. Be sure to stop for a treat at the Toy Museum cafe on Suomenlinna!

For architecture, visit the train station and take a walking tour of the Art Nouveau buildings east of the harbor. For museums, there is an excellent modern art museum (Kaisma) and Finish History/Culture Museum (all nearby the train station). Have a snack/tea/coffee in the glass coffee house in the main park. Enjoy a concert or people watching in the park.

I like Suomolina Island and the center/port area. I wasn't particularly impressed with the Rock Church. If you really like contemporary architecture (not really modern), you may like the church a lot. For us, it wasn't worth the tram ride for a ten-minute look inside. We didn't visit the open air museum outside of town. If I had more time, that might have been next on my list.