Sure, it's got solar panels on the roof, but let's face it — the world's largest floating island, which hosts an entertainment complex catering to the first world denizens of Seoul, South Korea, isn't exactly carbon neutral. That doesn't mean it isn't a valuable addition to the corpus of public works projects as thought experiments in how to create a sustainable, climate disaster-proof future.

Viva, the largest in a chain of three artificial islands, weighs in at 2,000 tons (minus buildings) and is held up by 24 giant airbags. Its 54 square meters of solar panels provide 6 kilowatts of electricity. It's kind of the Survivaball of new urbanism — self-contained and able to weather even the most drastic changes in sea level. So South Korean businessmen won’t have to give up restaurant meals and arcade games, no matter how bad climate change gets!