Although Reston is the home of the National Wildlife Federation headquarters, their certification was achieved before NWF moved its offices to Reston in 2001. Reston was built as a planned community in the 1970s with homes organized into clusters and surrounded by open space. The certification project was led by the Reston Association, the second largest homeowners association in the country. In addition to NWF Community Wildlife Habitat certification, Reston has received the Green Community Award, the Tree City Award and their nature center has been declared an urban wildlife sanctuary by the Institute for Urban Wildlife.