Alex Steffen: The shareable future of cities.
Worldchanging founder and planetary thinker Alex Steffen gives a whirlwind tour of inspirational ideas for re-thinking our rapidly urbanizing future. Concepts include: Infill, Urban Retrofitting, Tentpole Density, Placemaking, Walkshed, Augmented Urbanism, Surplus Capacities, Passivhaus, Green Infrastructure. [via TED.com]