It sounds like something out of a sci-fi novel, but designers in China have come up with some pretty realistic designs for an half underwater half floating city. The same team is behind the construction of a 31 mile long brings connecting Hong Kong, Macau and Zhuhai. Some engineers feel the same construction techniques used to complete the bridge would make the futuristic city possible.
There are some investors looking at the designs for actual consideration but many are skeptical the project will ever take flight due to cost. In the meantime we can dream about such cool ideas by checking out the amazing concept art.[Source]