7 Of The Most Ambitious Plans To Transform The World's Iconic Cities

As Istanbul prepares to open the Eurasia Bosphorus tunnel, a 3.4 mile (5.4 km) long underwater double-bridge near the Mamaray Tunnel, a Zaha Hadid plan aims to piggyback on the infrastructure growth by redeveloping waterfront industrial wasteland. 

By building the Kartal Pendik plan on 1,300 acres of land, Istanbul can have a new business center with concert halls, museums, theaters, hotels and a marina atop existing key transportation lines—both rail and vehicular—so the addition of major developments allows growth without requiring additional infrastructure. 

Pick your proposal, but all sorts of concepts put artificial islands around Manhattan for a litany of reasons. Some want to expand space for parks, greenspace and even pools. And then there are designed to protect the city from storms, perhaps even capturing tidal energy in less dire times. 

The first of these plans to actually get the go-ahead is the 2.7-acre Pier55 project, which will see a floating island built between between piers 54 and 56 on Manhattan's west side to serve as a public park with lawns, paths, and space for community events. 

It may take up to $26 billion (£20 billion) —and even that is an estimate—but Japanese company Shimizu Corp has a plan for an underwater eco-city dubbed Ocean Spiral. Designed to house 5,000 people and draw energy from the seabed, this Tokyo-based concept has the underwater structure stretching from the surface down about nine miles in a spiral shape.

The top would be a floating surface and then, inside the corkscrew you'd find  a business and residential zone and a factory at the bottom for creating energy through ocean thermal energy conversion, using the sea's temperature difference at varying depths. With the backing of the government, private industry, and academics, the idea will no doubt be the subject of further research. That doesn't mean it will ever happen, though. 

With a continuing rise of pollution, Paris has continued to ban cars in various parts of downtown, expanding the reach of no-car zones.  Just this fall Paris banned all vehicles from the Right Bank expressway along the Seine River, instead turning the area into a pedestrian-only playground with grass, cycling, and landscaping. As a result, Paris has started to think about its water and waterfront in a new way; get ready for some river taxis.  

To make transportation a rapid process, new fiberglass and high-density foam taxis, which can carry five people atop a foiled hull to reduce water drag by raising the hull above the water level, will get the world's first test run in Paris in spring 2017. 

Long live the pedestrians of Barcelona. Starting this fall, the city created additional superblocks, groupings of 12 city blocks into a mini-grid that have eliminated most vehicles. The only vehicles allowed in are from those who live within the grid—and at very strict speed limits—as all others must go around the grid to make the area more pedestrian-friendly. 

Barcelona started the concept in 1993 and added another superblock about a decade ago, but the city hopes to have five new ones by 2018 in an effort to reduce pollution and promote walking and cycling. 

Rotterdam knows water. With a city largely below sea level—a whole country, pretty much—the Dutch have become stellar at dealing with uncompromising water. So they float. Rotterdam already prototype floating structures, the Floating Pavilion that bubble up with three domes in the harbor. It functions as a parking structure but easily turns into a water holding tank. 

Moreover these structures can function as floating foundations. As the Dutch look at ways to deal with rising seas, entire communities may get built with floating foundations, allowing buildings to go amphibious, floating when needed and able to live on dry land, when dry land exists.

Urban infill will take a unique form in Stockholm, if Anders Berensson Architects has its way. The plan not only calls for taking over currently empty plots in the downtown area, but also grabbing hold of a grouping of railway tracks downtown to create a trail of high-rises, each with an undulating building height to merge with the city, each connected with a skywalk feature. Not only would the plan offer density, but it would help create a new vertical level citywide, whether for business or residential needs.