As a child I recall walking to the local corner market with my friends to buy penny candy. I also recall endless summer hours playing outdoors until our parents made that final call to come inside and wash up for bed. We never gave a second thought to riding our bicycles to each other's homes, which were sometimes many blocks away. Why is it that today's kids don't experience the same level of independence and outdoor activity that I did? Some experts blame a lack of physical activity on computers and television. Parents say neighborhoods aren't safe. I believe that changes in the built environment, consisting of man made structures and community infrastructure, have been a major factor in our lack of healthy lifestyles leading to such health conditions as childhood obesity. Neighborhoods have changed much since I was young, both physically and socially. Many of the corner markets don't exist anymore and some of the streets I used to ride along have become major roads that are dangerous for pedestrian activity. We now have an opportunity to change the built environment and should aspire to work together to improve the physical design as well as social and economic development of communities, which will result in healthy, sustainable places in which we all want to live.