World's First Underwater City Making Waves in Design Circles

— -- A new design for the world's first ever underwater city could mean some of your future neighbors will have scales and dorsal fins.

Searching for a way to combat the challenges coastal cities face with rising sea levels, a Japanese firm called Shimizu Corporation is presenting aquatic architecture as a possible solution. Titled "Ocean Spiral," the proposed $26 billion project would house 5,000 residents inside of a 500-meter sphere "city" that floats in the deep sea "like a spaceship," according to a recent statement by the company.

"Breaking free from past patterns of land development, which have focused mainly on efficiency, this plan is intended to promote true sustainability while maximizing use of the deep sea's resources," write the designers, who are currently working with Japanese universities and national agencies to work through various details.

Tethered to the ocean floor by ballasts, the city would be protected by a sea wall from larger waves, according to diagrams. Shimizu also seeks to make the city entirely sustainable, with fisheries providing food for its inhabitants, a desalinization filter offering unlimited fresh water, power made from thermal energy conversion and reuse of carbon dioxide emissions by microorganisms living on the sea floor.

While the design is fantastical compared with current land-based living environments, the company insists its idea is viable and is exploring ways to build the concrete structure under the sea.