By Jillian Eugenios, Steve Hargreaves and Aimee Rawlins @CNNMoney October 10, 2014: 5:55 PM ET
D.C.'s former planning director Harriet Tregoning spent several years working to transform the city with initiatives around environmental sustainability and neighborhood development. (Tregoning recently left to take a job at the U.S. Department of Housing and Urban Development.)
She rewrote the city's zoning code, which hadn't changed in half a century, promoting more pedestrian-friendly walkways and installing the city's first bike-share program. The city has also poured resources into early childhood education, and the initiatives seem to be working: Preschool attendance improved by 10% between 2007 and 2012.
With stream corridors that double as public parks and green living initiatives, the city is leading the way when it comes to going green. Its residents and businesses are a big part of the success: Their use of solar and wind power helped the city win first place in the the EPA's green power competition for the third year in a row. (Photo: Shutterstock) --J.E.