Floating modular city

Someday in the future, we will run out of usable land on earth and we will start to build our future cities on the sea. I imagine modular floating cities like this one I designed for the Cities of the Future design contest. About my City of the Future:The floating city will be built out of hexagonal pontoons that are connected by bridges above sea level. Each pontoon can be a self-sustaining island, or be connected to a larger city. Pontoons can have housing units, hotels, offices, beaches, parks, harbours, musea, factories, shopping malls, etc. The interconnected pontoons will form a walkable city above sea level, while faster public transport systems will be available below for longer travel distances inside the city. The hexagonal pontoons will be manufactured on land by massive 3D-printers, which can print all the required infrastructure right into the structure. The bridges can also be 3D-printed in stainless steel. About the model:Pontoons are printed separately and connected wit