Cool story, it seems you had fun here.

Btw...

The first island you visited (the one with the U-boat) is called Suomenlinna.

The zoo you mentioned is Korkeasaari, and while it's true you can take a ferry to get there, one can also take a metro to Kalasatama and walk across a bridge, or take the bus 16 from Rautatientori. :)

I agree that Linnanmäki is quite expensive. I took the Leo & Miro there this Summer and it practically cost us a hand and a leg. ;)

Serena... It's been a while since I've personally been swimming there, last time I was a kid. A couple of years ago though me and my father took Leo there and he seemed to like all the activities there. It rained a drizzle all the time and me and my dad were having a beer while Leo swam. (I had skin problems so I couldn't join him.)

I'm planning to take the boys to Serena some time in the future though.

Thanks for sharing your vacation photos and stories with us. :)