One of the "greenest" buildings in the U.S., the Natural Resources Defense Council's Washington D.C. office was built in 1996.  This environmentally-friendly building was commissioned by the American Association for the Advancement of Science to be an example of outstanding environmental practices.  The building encompasses some of the best commercially-available materials and technologies used to minimize consumption of energy and resources and maximize the use of natural. recycled and non-toxic materials.   Straw walls, wheatboard, and natural linoleum are only a few examples of materials implemented into this eco-friendly, aesthetically pleasing, economical building. 
NRDC's "green" office is located in a new building designed by Henry Cobb, of the renowned architectural firm of Pei, Cobb, Freed, and Partners. The Croxton Collaborative, a New York firm, was responsible for the energy and environmental features of the building, which include an air conditioning system free of chemicals that harm the ozone layer, as well as other additional innovative architectural and engineering features that help cut energy consumption by 50%.