A fresh and cheerful journey through an under-explored but ubiquitous aspect of our urban environment: the window air conditioning unit.

From a personal story of industrial decline to a national exploration of energy production, the artist discusses the themes that connect his body of work, including his current exhibition of photographs of some of New York's extraordinary and idiosyncratic trees.

"The city can be likened to a living microbe."

In the final installment of a Country of Cities, Vishaan pens a love letter to Japan, a country that has shaped his beliefs in the importance of dense urban living.

Janette Kim and Erik Carver discuss Underdome, an ambitious attempt to classify contending energy agendas and to examine their implications for public life.

As oil spills into the Gulf, blood spills in the streets of Greece, and cash spills from terrorist wallets into the hands of willing airline agents, one wonders who can clean up this mess. We tell our children to clean up after themselves, but can we? Disciplining a child is a perilous affair, but in the end self-discipline is the challenge. Self-discipline requires introspection, but how much of it can we muster in a world careening towards 9 billion people?

Vanessa Keith explores some simple yet radical ways to retrofit our urban building stock to address a chief cause of climate change: tropical deforestation.

Jeff Maki explains Manhattan's District Steam Service as a case study in how citizens can engage in the maintenance of infrastructure.

Architects Jenny Broutin and Carmen Trudell reflect on the development of their prototype for energy generating revolving doors, offering a case study for other innovators.

The energy revolution in the waterways is only beginning. Locally, the currents along this stretch of the East River make it a logical place to start.