When it comes to global cities, New York City may be one of the most prominent - but it is also relatively young. Just 400 years ago, Manhattan island was mostly covered in forests and marshes. In his talk at TEDx Long Island City, Eric Sanderson discusses the city's radical changes in land use over the past four centuries, and begins to contemplate what the next four might look like. How can we take a city like New York and make it as efficient as the forest it replaced? In a bid to uncover the ideas that might make this possible, he introduces Manhatta 2409 - an online tool which maps/compares the historic and current land use of Manhattan and allows users to propose new uses. Learn more in the video above.