Well, not really, but while some grow towards the sky, the Finnish capital grows in the opposite direction. Helsinki is bound by sea on one side and buildings on the other, when one counts in the fact that under the city lies a shallow bedrock the underground construction becomes somewhat painless and cheap. Such is the case, that at this moment the city already has a swimming pool complex, a church, a hokey rink and a shopping area encrusted beneath it.
Some of the advantages are quite apparent, like the fact the it contains outward expansion, but others not some much, like the greenest data centre in the world, that uses sea water to cool itself and manages to channel the heat it generates to help warm the city.
More info here.
