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.

"e²: the economies of being environmentally conscious" is an ongoing PBS documentary series about solutions to the world's most pervasive environmental challenges. The series continues its flagship coverage of sustainable architecture with "e² design season three," featuring innovations in green building and planning from around the globe. Check your local PBS listings for television broadcast dates in your area.

The "e²" series and its video podcasts are produced by kontentreal, and distributed within the United States by PBS. More information is available at pbs.org/e2/ and e2-series.com/