Photographer and architect Charles Giraudet documents the architecture of a sprawling hospital complex on Roosevelt Island on the eve of its demolition, and captures remnants of the life of the building and the innovative medical facility it once was.

Juliette Spertus discusses her exhibit - which combines infrastructure, New York history and alternative urban futures - about Roosevelt Island's trash collection system.

As cities demand more efficient transit systems, Steven Dale argues for thinking off the road and outside the subway, and thinks that Cable-Propelled Transit could be our answer.

Irene Cheng and Brett Snyder share the inspiration behind their iPhone app and pose questions sparked by their research. Read their story and then go tour the unbuilt city.