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With the upcoming release of Bioshock Infinite and its very lovely concept art, I began wondering about the fantastic cityscapes the world of Bioshock offers. In their universe, by 1912 we have the floating city of Columbia kept aloft by hot air balloons and jet turbines, and by 1960 we have the underwater metropolis of Rapture. Obviously the construction and upkeep of both is completely ASB, but I'm curious as to your thoughts as to which city would be more plausible to exist given technological restraints.
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