I think we're going to start to see a new model of civic advocacy where people get together once in a while to protest, but it's more about an ongoing, sustained engagement in issues, networks and communities about which people care.

We have to craft new political realities, not only in places like India, Afghanistan, Kenya, Pakistan, but here at home as well. Another world is possible.

At its very heart, Worldchanging is about using the best of people's new ideas, bringing them together and applying them to the massive problems that we all face.

Copenhagen has done a remarkable job creating streets that are focused on bicycles and pedestrians.

Urban retrofitting: creating different sorts of spaces and uses out of places that are already there.

Cities generate most of the global economy, and most of its energy use, resource demands and climate emissions. How we build cities over the next decades will largely determine whether we can deliver a bright green future.

We get so little news about the developing world that we often forget that there are literally millions of people out there struggling to change things to be fairer, freer, more democratic, less corrupt.