But they didn't know exactly how, so they launched a competition called Rebuild by Design. Ideas came in from architects and urban planners, all of them aimed at fighting rising tides with some solution better than levees. The hope was to create a coastline intrinsically resilient against floods.

Bjarke Ingels' Copenhagen and New York-based architecture firm BIG is one of six winners announced this week. The proposal is called the Big U, and it won $335 million to buttress Manhattan in preparation of the next superstorm. The other winners will focus on the Bronx, Staten Island, Long Island, and New Jersey.

The Big U will stretch eight miles along Manhattan's coastline, looping south from West 57th Street and then back up to East 42nd Street—a perimeter that hugs the area of Manhattan hit by the blackout. Much of the protection offered by the Big U will be from elevation. But unlike standard dikes, which can actually trap water, the plan calls for a more organic, sloped barrier that's built into the landscape.