Today, food travels an average of 1,500 miles from its production source to plate. Now, however, the end of cheap, abundant fuel is leading to the end of cheap food. Unpredictable fossil fuel costs and federal ethanol policy are both reshaping the global food economy.

Paris' citywide bike-sharing plan, Velib', has been so successful that the mayor wants to create a similar system for cars. Autolib', as it would be called, could offer a reliable and affordable alternative to driving personal vehicles in the city's congested streets. Some, however, feel that giving people the option to use a car in lieu of public transport is a step backward.

The majority of the world's population is now urban, making cities major sources of greenhouse gas emissions. In response, leaders from 40 cities met in London to tackle the challenge of making urban areas less polluting. The result is a worldwide network of cities - named C40 - that shares innovative strategies and advances climate change policy on the political agenda.

The Make It Right Foundation - founded by celebrity activist Brad Pitt - made history in storm-ravaged New Orleans by placing 150 pink symbolic homes in the city's hardest hit neighborhood, the Lower Ninth Ward. Each of Pitt's pink houses represents a sustainable home that will eventually be built in its place as money is raised by the foundation. Thirteen architects from around the world were recruited by Make It Right to design innovative, affordable, sustainable housing, which would also ensure the strongest protection possible against volatile weather.

The storm surge of Hurricane Katrina could have been mitigated had New Orleans' wetlands remained undeveloped. Now, citizens of the city's Lower Ninth Ward have begun the restoration of Bayou Bienvenue, which runs along the devastated neighborhood's northern border.

Melbourne, Australia's Council House 2, or CH2, has set a new standard for sustainable building design. While it employs established sustainable technologies, like energy and water conservation, the design includes many features that enhance the quality of the indoor environment.

His Highness the Aga Khan, spiritual leader of the Ismaili Muslims, has deep ancestral roots in the city of Cairo. His sponsorship of numerous social and economic development projects is grounded in the principle that people should be active participants in their communities and cultures.

Dutch architect Frits van Dongen discusses his building, The Whale. The Whale is the centerpiece of Borneo Sporenburg, a high-density urban housing development situated on Amsterdam's eastern docklands. Van Dongen describes how many units in the building do not share the same floor plan.

During his tenure as mayor of Bogota, Colombia, Enrique Penalosa was both revered and scorned for his urban planning and transportation policies. His public works projects, which largely favored the pedestrian experience, were unlike anything previously built in Bogota. Penalosa describes the environmental and social importance of minimizing automobile culture.

Architect Thom Mayne describes his philosophy toward sustainability and design. Mayne, a Pritzker Prize-winner and the architect of the San Francisco Federal Building, is a maverick and a leader in his field. He believes that people will have to adapt to new, sustainable building designs now and into the future.