After Hurricane Katrina devastated this once-thriving city, the population plummeted from 450,000 to as low as 100,000. Since 2005, however, New Orleans has been rebuilding slowly through community-based programs and volunteer organizations that  have brought residents closer than ever. Also, as New Orleans rebuilds, the city is looking to become eco-friendly. Global Green, the organization leading that charge, is building homes that qualify for the highest level of certification from the U.S. Green Building Council.