Portland is a city that successfully implemented a plan for transit-oriented development. Its urban planners made the public domain more appealing and accessible by emphasizing density and pedestrian travel. These transit policies are credited with spurring urban rejuvenation in Portland and many cities, while slowing the postwar dominance of the suburbs.

Aviation: The Limited Sky

e2 is an ongoing PBS documentary series that chronicles efforts to solve the world's most pressing ecological challenges. From energy consumption to design efficiency, policy to industry, the series documents the innovators whose work is reducing humans' impact on the environment. Interviews with experts, policymakers and pioneers across a variety of disciplines offer a firsthand account of the complex environmental challenges that we face, as well as the possibility that pragmatic solutions are within reach. The series is narrated by Brad Pitt and Morgan Freeman. Each episode is supplemented by a video podcast that features new footage and unseen interview excerpts, providing further insight into the social and environmental issues that series examines. Produced by kontentreal, new episodes of e2 release on PBS member stations every Tuesday beginning September 2, 2008. Check your local listings. Major corporate support for e2 is provided by Autodesk.