City planning is a big problem faced by cities around the world; big and small. While the developed world is concerned about utilizing the small space available to house more people. The developing world is scratching their head to find solutions to problems arising from rapid urbanization.
Helsinki is a Finnish city, I think it is its biggest, is planning to its future development now itself. They are running a competition with big CASH prizes. The competition seems to be finished, and you can see the best entries. The contest is called Greater Helsinki Vision 2050