U.S. Treasury Building, Washington, D.C.
One of Washington D.C.,'s most prominent structures, the U.S. Treasury Building, was built in the first half of the 19th century. It is one of the oldest federal structures in the capitol and was named as a National Historic Landmark in 1972. In 2011, after a series of upgrades, the building was given LEED Gold status.
More efficient heating and cooling systems, a heavier reliance on natural light sources, and new policies on sustainable supplies and landscape management all helped the Treasury building's greening efforts. There is a practical aspect to these new environmentally-friendly features. As a government institution, it is funded by taxpayers, so in a small way, less energy consumption inside the building means fewer tax dollars spent on day-to-day operations.