Floating Cities

[Dave]

The idea of a floating city has been around for ages. Key benefits include maritime economic advantages that would make Switzerland jealous. Operators are standing by, be the first to join Jimmy Buffet City!

Floating around the globe, drifting from country to country, never staying in one place long enough to get bored … 
If you like travelling, life on the Freedom Ship, the world’s first floating city, sounds perfect.
There’s only a couple of hitches – it’s not built yet, and it’s going to look an awful lot like a multi-storey carpark when it is.

Full story here: http://www.dailymail.co.uk/sciencet...-hospital-parks-airport-50-000-residents.html

Designed by the Florida-based Freedom Ship International, the floating city, concept pictured, is set to cost $10 billion and weigh 2.7 million tonnes - making it too large to ever dock. The ship would spend the whole time at sea, circling the globe once every two years, powered by solar and wave energy

There are some competing versions in the works as well

More here on this design:
http://inhabitat.com/underwater-skyscraper-is-a-self-sufficient-city-at-sea/waterscraper-ed06/

Here's another concept, Moses

Moses is a decentralized, self-sustaining city unit, populated by approximately 25,000 inhabitants, which offers the transition of men from land to sea, so that the land could be used for food production and the Earth could start its process of self-regeneration from the negative human impact. It functions independently as a city-unit, as well as a cluster of units, which share information, energy, and goods.

Each city-unit is placed on the intersection of perpendicular traffic lanes, which form the grid that serves as a connection between cities and land through a network of ultra fast trains.

Moses takes maximum advantage of its offshore location to produce renewable energy by two main systems. It consists of two structures that can rotate independently to utilize wind and water flow energy.

Full story, and some great expanded pictures, on the Moses concept here:
http://www.evolo.us/competition/moses-a-decentralized-floating-network-of-skyscraper-cities/