Density, short blocks, address the street, social gathering places, and biophilic design

"American cities are pretty much made for cars, which means they're not very easy for humans to navigate. And when you consider that cities are supposed to be made for humans to live in -- and that by 2050, two-thirds of the global population will live in cities, which already account for 70 percent of the planet's carbon emissions -- that's a bit of a problem."

"We talked to Dan Burden, walkability expert, on what factors are most important to transform our cities into places that are easier and more fun to live in, and less impactful on the ol' climate at the same time."