We recently spent a very nice 24 hours in Helsinki, Finland before crossing the strait to Tallinn, Estonia. Helsinki is quite a modern city and its delights are subtle. We very nearly didn't go to the Church in the Rock, having failed to realise that it's one of the top tourist attractions. You wouldn't know it from the humble location in the middle of a rather nondescript residential area.
Built in the late 1960s the church is sunk into the bedrock with just a domed roof poking above the natural lie of the land. It's really not much to look at from the outside, but internally it's a symphony of modernist concrete, rough-hewn stone, glass, wood and polished copper. It really speaks craftsmanship and slightly old fashioned Scandinavian design. It also has fantastic acoustics - there was a woman playing a grand piano as we wandered around, which just set it all off perfectly.