For the last twenty five years, America has built-up the suburbs. But now Americans are beginning to rethink whether these communities are environmentally sustainable. Joining The Takeaway is James Howard Kunstler, one of the urban thinkers gathering in Denver this week for the Congress for New Urbanism. He’s the author of "The Long Emergency: Surviving the Converging Catastrophes of the 21st Century."

This week The Takeaway is examining Denver as a laboratory for how the American city and surrounding suburbs are changing. The so-called "new urbanists" are pushing for more walkable, mixed-use (and mixed price) communities. They are gathering in Denver this week for the Congress on New Urbanism.

Matt Dellinger, transportation writer, joins The Takeaway to talk about who he's met and what he's learned while on safari in downtown Denver.

Follow along on The Takeaway's Urban Safari series.